2010
ASME Boiler and
Pressure Vessel Code
AN INTERNATIONAL CODE
VIII
Division 1
Rules for Construction of
Pressure Vessels
INTENTIONALLY LEFT BLANK
A N I N T E R N AT I O N A L CO D E
2010 ASME Boiler &
Pressure Vessel Code
2010 Edition
July 1, 2010
VIII
Division 1
RULES FOR CONSTRUCTION
OF PRESSURE VESSELS
ASME Boiler and Pressure Vessel Committee on Pressure Vessels
Three Park Avenue • New York, NY • 10016 USA
Date of Issuance: July 1, 2010
(Includes all Addenda dated July 2009 and earlier)
This international code or standard was developed under procedures accredited as meeting the criteria for American National
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Library of Congress Catalog Card Number: 56-3934
Printed in the United States of America
Adopted by the Council of the American Society of Mechanical Engineers, 1914.
Revised 1940, 1941, 1943, 1946, 1949, 1952, 1953, 1956, 1959, 1962, 1965, 1968, 1971, 1974, 1977, 1980, 1983, 1986,
1989, 1992, 1995, 1998, 2001, 2004, 2007, 2010
The American Society of Mechanical Engineers
Three Park Avenue, New York, NY 10016-5990
Copyright © 2010 by
THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS
All Rights Reserved
CONTENTS
List of Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Statements of Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Summary of Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of Changes in Record Number Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction
xxv
xxvii
xxix
xxx
xlii
xlviii
.......................................................................
1
SUBSECTION A
GENERAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
Part UG
General Requirements for All Methods of Construction and
All Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
8
UG-1
Materials
UG-4
UG-5
UG-6
UG-7
UG-8
UG-9
UG-10
UG-11
UG-12
UG-13
UG-14
UG-15
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forgings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Castings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pipe and Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welding Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Material Identified With or Produced to a Specification Not Permitted by
This Division, and Material Not Fully Identified . . . . . . . . . . . . . . . . . . . . . . . . .
Prefabricated or Preformed Pressure Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bolts and Studs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nuts and Washers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rods and Bars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Product Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
11
13
13
13
13
Design
UG-16
UG-17
UG-18
UG-19
UG-20
UG-21
UG-22
UG-23
UG-24
UG-25
UG-26
UG-27
UG-28
UG-29
UG-30
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Methods of Fabrication in Combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Materials in Combination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Special Constructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Design Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Design Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Loadings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Castings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Linings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells Under Internal Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells and Tubes Under External Pressure. . . . . . . . . . . . . . . . . . . . .
Stiffening Rings for Cylindrical Shells Under External Pressure . . . . . . . . . . . . .
Attachment of Stiffening Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
14
14
14
15
16
16
16
18
18
19
19
20
23
25
iii
8
9
9
9
9
10
UG-31
UG-32
UG-33
UG-34
UG-35
Tubes, and Pipe When Used as Tubes or Shells . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Formed Heads, and Sections, Pressure on Concave Side . . . . . . . . . . . . . . . . . . . .
Formed Heads, Pressure on Convex Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unstayed Flat Heads and Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other Types of Closures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27
29
30
33
37
Openings and Reinforcements
UG-36
Openings in Pressure Vessels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-37
Reinforcement Required for Openings in Shells and Formed Heads . . . . . . . . . .
UG-38
Flued Openings in Shells and Formed Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-39
Reinforcement Required for Openings in Flat Heads. . . . . . . . . . . . . . . . . . . . . . . .
UG-40
Limits of Reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-41
Strength of Reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-42
Reinforcement of Multiple Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-43
Methods of Attachment of Pipe and Nozzle Necks to Vessel Walls . . . . . . . . . .
UG-44
Flanges and Pipe Fittings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-45
Nozzle Neck Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-46
Inspection Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38
41
44
44
46
46
51
52
53
54
54
Braced and Stayed Surfaces
UG-47
Braced and Stayed Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-48
Staybolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-49
Location of Staybolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-50
Dimensions of Staybolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
56
57
57
57
Ligaments
UG-53
UG-54
UG-55
Ligaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lugs for Platforms, Ladders, and Other Attachments to Vessel Walls . . . . . . . .
57
59
59
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cutting Plates and Other Stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Material Identification (See UG-85) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair of Defects in Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forming Shell Sections and Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Permissible Out-of-Roundness of Cylindrical, Conical, and Spherical
Shells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tolerance for Formed Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lugs and Fitting Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Holes for Screw Stays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Charpy Impact Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
62
62
62
62
62
Fabrication
UG-75
UG-76
UG-77
UG-78
UG-79
UG-80
UG-81
UG-82
UG-83
UG-84
UG-85
Inspection and Tests
UG-90
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-91
The Inspector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-92
Access for Inspector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-93
Inspection of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-94
Marking on Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-95
Examination of Surfaces During Fabrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-96
Dimensional Check of Component Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-97
Inspection During Fabrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-98
Maximum Allowable Working Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
iv
63
64
65
65
65
71
71
72
72
72
73
73
74
74
74
UG-99
UG-100
UG-101
UG-102
UG-103
Standard Hydrostatic Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pneumatic Test (See UW-50). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Proof Tests to Establish Maximum Allowable Working Pressure. . . . . . . . . . . . .
Test Gages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nondestructive Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
74
76
76
81
82
Marking and Reports
UG-115
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-116
Required Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-117
Certificates of Authorization and Code Symbol Stamps . . . . . . . . . . . . . . . . . . . . .
UG-118
Methods of Marking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-119
Nameplates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-120
Data Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
82
82
83
86
86
87
Pressure Relief Devices
UG-125
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-126
Pressure Relief Valves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-127
Nonreclosing Pressure Relief Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-128
Liquid Pressure Relief Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-129
Marking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-130
Code Symbol Stamp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-131
Certification of Capacity of Pressure Relief Devices . . . . . . . . . . . . . . . . . . . . . . . .
UG-132
Certification of Capacity of Pressure Relief Valves in Combination With
Nonreclosing Pressure Relief Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-133
Determination of Pressure Relieving Requirements . . . . . . . . . . . . . . . . . . . . . . . . .
UG-134
Pressure Settings and Performance Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-135
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-136
Minimum Requirements for Pressure Relief Valves. . . . . . . . . . . . . . . . . . . . . . . . .
UG-137
Minimum Requirements for Rupture Disk Devices . . . . . . . . . . . . . . . . . . . . . . . . .
UG-138
Minimum Requirements for Pin Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UG-140
Overpressure Protection by System Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figures
UG-28
UG-28.1
UG-29.1
UG-29.2
UG-30
UG-33.1
UG-34
UG-36
UG-37
UG-37.1
UG-38
UG-39
UG-40
UG-41.1
Diagrammatic Representation of Variables for Design of Cylindrical
Vessels Subjected to External Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagrammatic Representation of Lines of Support for Design of
Cylindrical Vessels Subjected to External Pressure . . . . . . . . . . . . . . . . . . . . . . .
Various Arrangements of Stiffening Rings for Cylindrical Vessels
Subjected to External Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Arc of Shell Left Unsupported Because of Gap in Stiffening
Ring of Cylindrical Shell Under External Pressure . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Methods of Attaching Stiffening Rings . . . . . . . . . . . . . . . . . . .
Length Lc of Some Typical Conical Sections for External Pressure. . . . . . . . . . .
Some Acceptable Types of Unstayed Flat Heads and Covers . . . . . . . . . . . . . . . .
Large Head Openings — Reverse-Curve and Conical Shell-Reducer
Sections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chart for Determining Value of F, as Required in UG-37 . . . . . . . . . . . . . . . . . . .
Nomenclature and Formulas for Reinforced Openings . . . . . . . . . . . . . . . . . . . . . .
Minimum Depth for Flange of Flued-In Openings . . . . . . . . . . . . . . . . . . . . . . . . . .
Multiple Openings in Rim of Heads With a Large Central Opening . . . . . . . . . .
Some Representative Configurations Describing the Reinforcement
Dimension te and the Opening Dimension d . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nozzle Attachment Weld Loads and Weld Strength Paths to Be
Considered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
v
88
89
90
93
93
95
95
99
100
100
101
101
105
107
109
20
21
26
27
28
32
35
39
41
42
44
47
48
50
UG-42
UG-47
UG-53.1
UG-53.2
UG-53.3
UG-53.4
UG-53.5
UG-53.6
UG-80.1
UG-80.2
UG-84
UG-84.1
UG-84.1M
UG-116
UG-118
UG-129.1
UG-129.2
Tables
UG-33.1
UG-37
UG-43
UG-45
UG-84.2
UG-84.3
UG-84.4
Examples of Multiple Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acceptable Proportions for Ends of Stays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example of Tube Spacing With Pitch of Holes Equal in Every Row . . . . . . . . .
Example of Tube Spacing With Pitch of Holes Unequal in Every Second
Row . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example of Tube Spacing With Pitch of Holes Varying in Every Second and
Third Row . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example of Tube Spacing With Tube Holes on Diagonal Lines. . . . . . . . . . . . . .
Diagram for Determining the Efficiency of Longitudinal and Diagonal
Ligaments Between Openings in Cylindrical Shells. . . . . . . . . . . . . . . . . . . . . . .
Diagram for Determining Equivalent Longitudinal Efficiency of Diagonal
Ligaments Between Openings in Cylindrical Shells. . . . . . . . . . . . . . . . . . . . . . .
Maximum Permissible Deviation From a Circular Form e for Vessels Under
External Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example of Differences Between Maximum and Minimum Inside
Diameters in Cylindrical, Conical, and Spherical Shells . . . . . . . . . . . . . . . . . . .
Simple Beam Impact Test Specimens (Charpy Type Test). . . . . . . . . . . . . . . . . . .
Charpy V-Notch Impact Test Requirements for Full Size Specimens for
Carbon and Low Alloy Steels, Having a Specified Minimum Tensile
Strength of Less Than 95 ksi, Listed in Table UCS-23 . . . . . . . . . . . . . . . . . . .
Charpy V-Notch Impact Test Requirements for Full Size Specimens for
Carbon and Low Alloy Steels, Having a Specified Minimum Tensile
Strength of Less Than 655 MPa, Listed in Table UCS-23. . . . . . . . . . . . . . . . .
Official Symbols for Stamp to Denote the American Society of Mechanical
Engineers’ Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Form of Stamping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Official Symbol for Stamp to Denote the American Society of
Mechanical Engineers’ Standard for Pressure Relief Valves . . . . . . . . . . . . . . .
Official Symbol for Stamp to Denote the American Society of
Mechanical Engineers’ Standard for Nonreclosing Pressure Relief
Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Values of Spherical Radius Factor Ko for Ellipsoidal Head With Pressure on
Convex Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Values of Spherical Radius Factor K1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Minimum Number of Pipe Threads for Connections . . . . . . . . . . . . . . . . . . . . . . . .
Nozzle Minimum Thickness Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Charpy Impact Test Temperature Reduction Below Minimum Design Metal
Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications for Impact Tested Materials in Various Product Forms. . . . . . . . .
Impact Test Temperature Differential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
52
56
58
58
58
59
60
61
63
63
65
67
68
82
86
93
94
30
43
53
55
69
69
69
SUBSECTION B
REQUIREMENTS PERTAINING TO METHODS OF
FABRICATION OF PRESSURE VESSELS. . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Part UW
Requirements for Pressure Vessels Fabricated by Welding . . . . . . . . . . . . . . . 111
General
UW-1
UW-2
UW-3
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Service Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Welded Joint Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
vi
Materials
UW-5
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Design
UW-8
UW-9
UW-10
UW-11
UW-12
UW-13
UW-14
UW-15
UW-16
UW-17
UW-18
UW-19
UW-20
UW-21
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Design of Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radiographic and Ultrasonic Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Joint Efficiencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Attachment Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Openings in or Adjacent to Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welded Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Minimum Requirements for Attachment Welds at Openings . . . . . . . . . . . . . . . . .
Plug Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fillet Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welded Stayed Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tube-to-Tubesheet Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flange to Nozzle Neck Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
114
114
115
115
116
116
125
125
126
136
137
137
138
140
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welding Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Qualification of Welding Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tests of Welders and Welding Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lowest Permissible Temperatures for Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cutting, Fitting, and Alignment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cleaning of Surfaces to Be Welded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alignment Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Spin-Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finished Longitudinal and Circumferential Joints . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fillet Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Miscellaneous Welding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair of Weld Defects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Peening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Procedures for Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sectioning of Welded Joints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surface Weld Metal Buildup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
140
141
142
142
142
143
143
143
144
144
144
144
145
145
146
147
147
Fabrication
UW-26
UW-27
UW-28
UW-29
UW-30
UW-31
UW-32
UW-33
UW-34
UW-35
UW-36
UW-37
UW-38
UW-39
UW-40
UW-41
UW-42
Inspection and Tests
UW-46
UW-47
UW-48
UW-49
UW-50
UW-51
UW-52
UW-53
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check of Welding Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check of Welder and Welding Operator Qualifications. . . . . . . . . . . . . . . . . . . . . .
Check of Postweld Heat Treatment Practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nondestructive Examination of Welds on Pneumatically Tested Vessels . . . . . .
Radiographic Examination of Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Spot Examination of Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technique for Ultrasonic Examination of Welded Joints . . . . . . . . . . . . . . . . . . . .
148
148
148
148
148
148
149
150
Marking and Reports
UW-60
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
vii
Pressure Relief Devices
UW-65
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
UW-54
Qualification of Nondestructive Examination Personnel . . . . . . . . . . . . . . . . . . . . . 150
Figures
UW-3
UW-16.2
UW-16.3
UW-19.1
UW-19.2
UW-20.1
UW-21
Illustration of Welded Joint Locations Typical of Categories A, B, C,
and D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Butt Welding of Plates of Unequal Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heads Attached to Shells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Attachment of Pressure Parts to Flat Plates to Form a Corner Joint. . . . . . . . . . .
Typical Pressure Parts With Butt Welded Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nozzle Necks Attached to Piping of Lesser Wall Thickness . . . . . . . . . . . . . . . . .
Fabricated Lap Joint Stub Ends for Lethal Service. . . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Types of Welded Nozzles and Other Connections to Shells,
Heads, etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Types of Small Standard Fittings. . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Types of Small Bolting Pads . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Forms of Welded Staybolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use of Plug and Slot Welds for Staying Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Types of Tube-to-Tubesheet Strength Welds . . . . . . . . . . . . . .
Typical Details for Slip-On and Socket Welded Flange Attachment Welds. . . .
Tables
UW-12
UW-16.1
UW-33
Maximum Allowable Joint Efficiencies for Arc and Gas Welded Joints. . . . . . . 117
Minimum Thickness Required by UW-16(a)(3)(a)(6) . . . . . . . . . . . . . . . . . . . . . . . 133
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Part UF
Requirements for Pressure Vessels Fabricated by Forging . . . . . . . . . . . . . . . 151
General
UF-1
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Materials
UF-5
UF-6
UF-7
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Forgings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Forged Steel Rolls Used for Corrugating Paper Machinery . . . . . . . . . . . . . . . . . . 151
Design
UF-12
UF-13
UF-25
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Head Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Corrosion Allowance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
UW-9
UW-13.1
UW-13.2
UW-13.3
UW-13.4
UW-13.5
UW-16.1
Fabrication
UF-26
UF-27
UF-28
UF-29
UF-30
UF-31
UF-32
UF-37
UF-38
UF-43
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tolerances on Body Forgings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Methods of Forming Forged Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tolerance on Forged Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Localized Thin Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welding for Fabrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair of Defects in Material. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair of Weld Defects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Attachment of Threaded Nozzles to Integrally Forged Necks and
Thickened Heads on Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
viii
113
114
119
123
124
125
126
127
134
136
137
138
139
141
152
152
152
152
153
153
153
154
155
155
Inspection and Tests
UF-45
UF-46
UF-47
UF-52
UF-53
UF-54
UF-55
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acceptance by Inspector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Forging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check of Heat Treatment and Postweld Heat Treatment. . . . . . . . . . . . . . . . . . . . .
Test Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tests and Retests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ultrasonic Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
155
155
155
155
156
156
156
Marking and Reports
UF-115
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Pressure Relief Devices
UF-125
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
Part UB
Requirements for Pressure Vessels Fabricated by Brazing . . . . . . . . . . . . . . . 157
General
UB-1
UB-2
UB-3
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Elevated Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Service Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Materials
UB-5
UB-6
UB-7
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Brazing Filler Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Fluxes and Atmospheres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Design
UB-9
UB-10
UB-11
UB-12
UB-13
UB-14
UB-15
UB-16
UB-17
UB-18
UB-19
UB-20
UB-21
UB-22
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Strength of Brazed Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Qualification of Brazed Joints for Design Temperatures up to the
Maximum Shown in Column 1 of Table UB-2. . . . . . . . . . . . . . . . . . . . . . . . . . .
Qualification of Brazed Joints for Design Temperatures in the Range
Shown in Column 2 of Table UB-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Joint Efficiency Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Application of Brazing Filler Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Permissible Types of Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Joint Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Joint Brazing Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nozzles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brazed Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low Temperature Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
157
158
158
158
158
158
159
159
159
160
160
160
161
161
Fabrication
UB-30
UB-31
UB-32
UB-33
UB-34
UB-35
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Qualification of Brazing Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Qualification of Brazers and Brazing Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buttstraps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cleaning of Surfaces to Be Brazed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clearance Between Surfaces to Be Brazed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ix
161
161
161
162
162
162
UB-36
UB-37
Postbrazing Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Repair of Defective Brazing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Inspection and Tests
UB-40
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UB-41
Inspection During Fabrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UB-42
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UB-43
Brazer and Brazing Operator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UB-44
Visual Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UB-50
Exemptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Marking and Reports
UB-55
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
162
162
163
163
163
163
163
Pressure Relief Devices
UB-60
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Figures
UB-14
UB-16
Examples of Filler Metal Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Some Acceptable Types of Brazed Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Tables
UB-2
UB-17
Maximum Design Temperatures for Brazing Filler Metal . . . . . . . . . . . . . . . . . . . 158
Recommended Joint Clearances at Brazing Temperature . . . . . . . . . . . . . . . . . . . . 160
SUBSECTION C
REQUIREMENTS PERTAINING TO CLASSES OF MATERIALS. . . . . . 164
Part UCS
Requirements for Pressure Vessels Constructed of Carbon and Low
Alloy Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
General
UCS-1
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Materials
UCS-5
UCS-6
UCS-7
UCS-8
UCS-9
UCS-10
UCS-11
UCS-12
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steel Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steel Forgings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steel Castings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steel Pipe and Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bolt Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nuts and Washers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bars and Shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
164
165
165
165
165
165
165
165
Design
UCS-16
UCS-19
UCS-23
UCS-27
UCS-28
UCS-29
UCS-30
UCS-33
UCS-56
UCS-57
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shells Made From Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells Under External Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stiffening Rings for Shells Under External Pressure . . . . . . . . . . . . . . . . . . . . . . . .
Attachment of Stiffening Rings to Shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Formed Heads, Pressure on Convex Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Requirements for Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radiographic Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
167
167
167
167
167
167
167
167
167
177
x
Low Temperature
UCS-65
UCS-66
UCS-67
UCS-68
Fabrication
UCS-75
UCS-79
UCS-85
Operation
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Impact Tests of Welding Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
177
178
183
189
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Forming Shell Sections and Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Heat Treatment of Test Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Inspection and Tests
UCS-90
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Marking and Reports
UCS-115
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Pressure Relief Devices
UCS-125
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Nonmandatory Appendix CS
UCS-150
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
UCS-151
Creep-Rupture Properties of Carbon Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
UCS-160
Vessels Operating at Temperatures Colder Than the MDMT Stamped on the
Nameplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Figures
UCS-66
UCS-66M
UCS-66.1
UCS-66.1M
UCS-66.2
UCS-66.3
Tables
UCS-23
UCS-56
UCS-56.1
UCS-57
UCS-66
Part UNF
General
UNF-1
UNF-3
UNF-4
Impact Test Exemption Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Impact Test Exemption Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reduction in Minimum Design Metal Temperature Without Impact
Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reduction in Minimum Design Metal Temperature Without Impact
Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagram of UCS-66 Rules for Determining Lowest Minimum Design
Metal Temperature (MDMT) Without Impact Testing . . . . . . . . . . . . . . . . . . . .
Some Typical Vessel Details Showing the Governing Thicknesses as
Defined in UCS-66. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Carbon and Low Alloy Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Postweld Heat Treatment Requirements for Carbon and Low Alloy Steels . . . .
Alternative Postweld Heat Treatment Requirements for Carbon and Low
Alloy Steels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness Above Which Full Radiographic Examination of Butt Welded
Joints Is Mandatory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tabular Values for Fig. UCS-66 and Fig. UCS-66M. . . . . . . . . . . . . . . . . . . . . . . .
179
182
186
187
188
190
166
169
177
177
184
Requirements for Pressure Vessels Constructed of Nonferrous
Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Conditions of Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
xi
Materials
UNF-5
UNF-6
UNF-7
UNF-8
UNF-12
UNF-13
UNF-14
UNF-15
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nonferrous Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forgings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Castings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bolt Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nuts and Washers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rods, Bars, and Shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
195
195
195
195
195
196
196
196
Design
UNF-16
UNF-19
UNF-23
UNF-28
UNF-30
UNF-33
UNF-56
UNF-57
UNF-58
UNF-65
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells Under External Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stiffening Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Formed Heads, Pressure on Convex Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radiographic Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Liquid Penetrant Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low Temperature Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
196
196
196
200
200
200
200
201
201
201
Fabrication
UNF-75
UNF-77
UNF-78
UNF-79
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forming Shell Sections and Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Requirements for Postfabrication Heat Treatment Due to Straining . . . . . . . . . . .
201
202
202
202
Inspection and Tests
UNF-90
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
UNF-91
Requirements for Penetrameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
UNF-95
Welding Test Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Marking and Reports
UNF-115
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Pressure Relief Devices
UNF-125
General Vessels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Appendix NF
NF-1
NF-2
NF-3
NF-4
NF-5
NF-6
NF-7
NF-8
NF-9
NF-10
NF-11
NF-12
Characteristics of the Nonferrous Materials (Informative and
Nonmandatory) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Magnetic Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Elevated Temperature Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low Temperature Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermal Cutting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Machining. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Metal Arc Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inert Gas Metal Arc Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Resistance Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xii
203
203
203
204
204
204
204
204
204
204
204
204
204
NF-13
NF-14
Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Special Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Tables
UNF-23.1
UNF-23.2
UNF-23.3
UNF-23.4
UNF-23.5
UNF-79
Nonferrous Metals — Aluminum and Aluminum Alloy Products . . . . . . . . . . . .
Nonferrous Metals — Copper and Copper Alloys . . . . . . . . . . . . . . . . . . . . . . . . . .
Nonferrous Metals — Nickel, Cobalt, and High Nickel Alloys. . . . . . . . . . . . . . .
Nonferrous Metals — Titanium and Titanium Alloys . . . . . . . . . . . . . . . . . . . . . . .
Nonferrous Metals — Zirconium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Postfabrication Strain Limits and Required Heat Treatment. . . . . . . . . . . . . . . . . .
Part UHA
Requirements for Pressure Vessels Constructed of High Alloy Steel . . . . . . 205
197
197
198
199
200
202
General
UHA-1
UHA-5
UHA-6
UHA-8
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conditions of Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
205
205
205
205
Materials
UHA-11
UHA-12
UHA-13
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Bolt Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Nuts and Washers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
Design
UHA-20
UHA-21
UHA-23
UHA-28
UHA-29
UHA-30
UHA-31
UHA-32
UHA-33
UHA-34
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells Under External Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stiffening Rings for Shells Under External Pressure . . . . . . . . . . . . . . . . . . . . . . . .
Attachment of Stiffening Rings to Shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Formed Heads, Pressure on Convex Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Requirements for Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radiographic Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Liquid Penetrant Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
208
208
208
208
208
209
209
209
209
209
Fabrication
UHA-40
UHA-42
UHA-44
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
Weld Metal Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
Requirements for Postfabrication Heat Treatment Due to Straining . . . . . . . . . . . 212
Inspection and Tests
UHA-50
UHA-51
UHA-52
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
Impact Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
Welded Test Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
Marking and Reports
UHA-60
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
Pressure Relief Devices
UHA-65
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
xiii
Appendix HA
Suggestions on the Selection and Treatment of Austenitic Chromium–
Nickel and Ferritic and Martensitic High Chromium Steels
(Informative and Nonmandatory) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
UHA-100
UHA-101
UHA-102
UHA-103
UHA-104
UHA-105
UHA-107
UHA-108
UHA-109
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Intergranular Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stress Corrosion Cracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sigma Phase Embrittlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heat Treatment of Austenitic Chromium–Nickel Steels . . . . . . . . . . . . . . . . . . . . .
Dissimilar Weld Metal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fabrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
885°F (475°C) Embrittlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tables
UHA-23
UHA-32
UHA-44
High Alloy Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Postweld Heat Treatment Requirements for High Alloy Steels . . . . . . . . . . . . . . . 210
Postfabrication Strain Limits and Required Heat Treatment. . . . . . . . . . . . . . . . . . 213
Part UCI
Requirements for Pressure Vessels Constructed of Cast Iron . . . . . . . . . . . . . 218
216
216
216
216
216
216
216
216
217
General
UCI-1
UCI-2
UCI-3
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Service Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Pressure–Temperature Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Materials
UCI-5
UCI-12
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Bolt Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Design
UCI-16
UCI-23
UCI-28
UCI-29
UCI-32
UCI-33
UCI-35
UCI-36
UCI-37
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells Under External Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dual Metal Cylinders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heads With Pressure on Concave Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heads With Pressure on Convex Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Spherically Shaped Covers (Heads) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Openings and Reinforcements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corners and Fillets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
218
219
219
219
219
220
220
220
220
Fabrication
UCI-75
UCI-78
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Repairs in Cast Iron Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Inspection and Tests
UCI-90
UCI-99
UCI-101
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
Standard Hydrostatic Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
Hydrostatic Test to Destruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
xiv
Marking and Reports
UCI-115
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Pressure Relief Devices
UCI-125
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Tables
UCI-23
UCI-78.1
UCI-78.2
Part UCL
Maximum Allowable Stress Values in Tension for Cast Iron . . . . . . . . . . . . . . . . 219
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
Requirements for Welded Pressure Vessels Constructed of Material With
Corrosion Resistant Integral Cladding, Weld Metal Overlay
Cladding, or With Applied Linings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
General
UCL-1
UCL-2
UCL-3
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Methods of Fabrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Conditions of Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Materials
UCL-10
UCL-11
UCL-12
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Integral and Weld Metal Overlay Clad Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Lining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
Design
UCL-20
UCL-23
UCL-24
UCL-25
UCL-26
UCL-27
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Working Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corrosion of Cladding or Lining Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells and Heads Under External Pressure . . . . . . . . . . . . . . . . . . . .
Low Temperature Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
224
224
225
225
225
225
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Joints in Integral or Weld Metal Overlay Cladding and Applied Linings . . . . . .
Weld Metal Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inserted Strips in Clad Material. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radiographic Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Examination of Chromium Stainless Steel Cladding or Lining . . . . . . . . . . . . . . .
Welding Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alloy Welds in Base Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fillet Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
225
225
225
226
226
226
226
227
227
227
Fabrication
UCL-30
UCL-31
UCL-32
UCL-33
UCL-34
UCL-35
UCL-36
UCL-40
UCL-42
UCL-46
Inspection and Tests
UCL-50
UCL-51
UCL-52
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Tightness of Applied Lining. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Hydrostatic Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Marking and Reports
UCL-55
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
xv
Pressure Relief Devices
UCL-60
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Part UCD
Requirements for Pressure Vessels Constructed of Cast Ductile Iron . . . . . 228
General
UCD-1
UCD-2
UCD-3
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Service Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Pressure–Temperature Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Materials
UCD-5
UCD-12
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Bolt Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Design
UCD-16
UCD-23
UCD-28
UCD-32
UCD-33
UCD-35
UCD-36
UCD-37
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells Under External Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heads With Pressure on Concave Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heads With Pressure on Convex Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Spherically Shaped Covers (Heads) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Openings and Reinforcements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corners and Fillets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
228
229
229
229
229
229
229
229
Fabrication
UCD-75
UCD-78
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
Repairs in Cast Ductile Iron Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
Inspection and Tests
UCD-90
UCD-99
UCD-101
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Standard Hydrostatic Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Hydrostatic Test to Destruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Marking and Reports
UCD-115
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Pressure Relief Devices
UCD-125
Tables
UCD-23
UCD-78.1
UCD-78.2
Part UHT
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Maximum Allowable Stress Values in Tension for Cast Ductile Iron,
ksi (MPa) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
Requirements for Pressure Vessels Constructed of Ferritic Steels
With Tensile Properties Enhanced by Heat Treatment. . . . . . . . . . . . . . . . . 232
General
UHT-1
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
xvi
Materials
UHT-5
UHT-6
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Test Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Design
UHT-16
UHT-17
UHT-18
UHT-19
UHT-20
UHT-23
UHT-25
UHT-27
UHT-28
UHT-29
UHT-30
UHT-32
UHT-33
UHT-34
UHT-40
UHT-56
UHT-57
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nozzles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conical Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Joint Alignment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corrosion Allowance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells Under External Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Structural Attachments and Stiffening Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stiffening Rings for Shells Under External Pressure . . . . . . . . . . . . . . . . . . . . . . . .
Attachment of Stiffening Rings to Shells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Formed Heads, Pressure on Concave Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Formed Heads, Pressure on Convex Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hemispherical Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Materials Having Different Coefficients of Expansion. . . . . . . . . . . . . . . . . . . . . . .
Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
233
233
234
234
234
234
237
237
237
237
237
237
237
238
238
238
238
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forming Shell Sections and Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heat Treatment Verification Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Methods of Metal Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Weld Finish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Structural and Temporary Welds. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Marking on Plates and Other Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
240
240
240
240
241
242
242
242
242
Fabrication
UHT-75
UHT-79
UHT-80
UHT-81
UHT-82
UHT-83
UHT-84
UHT-85
UHT-86
Inspection and Tests
UHT-90
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Marking and Reports
UHT-115
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Pressure Relief Devices
UHT-125
Figures
UHT-6.1
UHT-6.1M
UHT-18.1
UHT-18.2
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
Charpy V-Notch Impact Test Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Charpy V-Notch Impact Test Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acceptable Welded Nozzle Attachment Readily Radiographed to Code
Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acceptable Full Penetration Welded Nozzle Attachments Radiographable
With Difficulty and Generally Requiring Special Techniques Including
Multiple Exposures to Take Care of Thickness Variations. . . . . . . . . . . . . . . . .
xvii
233
233
235
236
Table
UHT-23
UHT-56
Part ULW
Ferritic Steels With Properties Enhanced by Heat Treatment. . . . . . . . . . . . . . . . . 237
Postweld Heat Treatment Requirements for Materials in Table UHT-23 . . . . . . 239
Requirements for Pressure Vessels Fabricated by Layered
Construction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Introduction
ULW-1
ULW-2
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Nomenclature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Material
ULW-5
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Design
ULW-16
ULW-17
ULW-18
ULW-20
ULW-22
ULW-26
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Design of Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nozzle Attachments and Opening Reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welded Joint Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
244
247
255
255
255
255
Welding
ULW-31
ULW-32
ULW-33
Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Welding Procedure Qualification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Performance Qualification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Nondestructive Examination of Welded Joints
ULW-50
ULW-51
ULW-52
ULW-53
ULW-54
ULW-55
ULW-56
ULW-57
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inner Shells and Inner Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Layers — Welded Joints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Layers — Step Welded Girth Joints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Butt Joints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flat Head and Tubesheet Weld Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nozzle and Communicating Chambers Weld Joints . . . . . . . . . . . . . . . . . . . . . . . . .
Random Spot Examination and Repairs of Weld . . . . . . . . . . . . . . . . . . . . . . . . . . .
259
259
259
262
262
262
262
263
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vent Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contact Between Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alternative to Measuring Contact Between Layers During Construction . . . . . .
265
265
265
265
Fabrication
ULW-75
ULW-76
ULW-77
ULW-78
Inspection and Testing
ULW-90
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
Marking and Reports
ULW-115
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
Pressure Relief Devices
ULW-125
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
xviii
Figures
ULW-2.1
ULW-2.2
ULW-17.1
ULW-17.2
ULW-17.3
ULW-17.4
ULW-17.5
ULW-17.6
ULW-18.1
ULW-22
ULW-32.1
ULW-32.2
ULW-32.3
ULW-32.4
ULW-54.1
ULW-54.2
ULW-77
Part ULT
Some Acceptable Layered Shell Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Layered Head Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transitions of Layered Shell Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Solid Head Attachments to Layered Shell Sections. . . . . . . . .
Some Acceptable Flat Heads and Tubesheets With Hubs Joining Layered
Shell Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Flanges for Layered Shells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Layered Head Attachments to Layered Shells . . . . . . . . . . . . .
Some Acceptable Welded Joints of Layered-to-Layered and Layered-to-Solid
Sections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Nozzle Attachments in Layered Shell Sections . . . . . . . . . . . .
Some Acceptable Supports for Layered Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Solid-to-Layered and Layered-to-Layered Test Plates . . . . . . . . . . . . . . . . . . . . . . .
.......................................................................
.......................................................................
.......................................................................
.......................................................................
.......................................................................
.......................................................................
245
246
248
249
251
252
253
254
256
258
260
261
261
261
263
264
266
Alternative Rules for Pressure Vessels Constructed of Materials
Having Higher Allowable Stresses at Low Temperature . . . . . . . . . . . . . . . 267
General
ULT-1
ULT-2
ULT-5
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Conditions of Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Design
ULT-16
ULT-17
ULT-18
ULT-23
ULT-27
ULT-28
ULT-29
ULT-30
ULT-56
ULT-57
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nozzles and Other Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thickness of Shells Under External Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stiffening Rings for Shells Under External Pressure . . . . . . . . . . . . . . . . . . . . . . . .
Structural Attachments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Postweld Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
268
268
268
268
268
268
268
268
273
273
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forming Shell Sections and Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Marking on Plate and Other Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
273
273
273
273
Fabrication
ULT-75
ULT-79
ULT-82
ULT-86
Inspection and Tests
ULT-90
ULT-99
ULT-100
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Hydrostatic Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Pneumatic Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
xix
Marking and Reports
ULT-115
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Pressure Relief Devices
ULT-125
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
Figure
ULT-82
Tables
ULT-23
ULT-82
Weld Metal Delta Ferrite Content. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Maximum Allowable Stress Values in Tension for 5%, 8%, and 9% Nickel
Steels, Type 304 Stainless Steel, and 5083-O Aluminum Alloy at
Cryogenic Temperatures for Welded and Nonwelded Construction . . . . . . . . . 269
Minimum Tensile Strength Requirements for Welding Procedure
Qualification Tests on Tension Specimens Conforming to QW-462.1. . . . . . . 274
Part UHX
Rules for Shell-and-Tube Heat Exchangers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
UHX-1
UHX-2
UHX-3
UHX-4
UHX-9
UHX-10
UHX-11
UHX-12
UHX-13
UHX-14
UHX-16
UHX-17
UHX-18
UHX-19
UHX-20
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Materials and Methods of Fabrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tubesheet Flanged Extension. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Conditions of Applicability for Tubesheets. . . . . . . . . . . . . . . . . . . . . . . . .
Tubesheet Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rules for the Design of U-Tube Tubesheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rules for the Design of Fixed Tubesheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rules for the Design of Floating Tubesheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bellows Expansion Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flanged-and-Flued or Flanged-Only Expansion Joints. . . . . . . . . . . . . . . . . . . . . . .
Pressure Test Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heat Exchanger Marking and Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
278
278
278
278
278
280
280
285
293
307
318
318
318
318
320
Terminology of Heat Exchanger Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Some Representative Configurations Describing the Minimum Required
Thickness of the Tubesheet Flanged Extension, hr . . . . . . . . . . . . . . . . . . . . . . . .
Integral Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tubesheet Geometry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Untubed Lane Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Curves for the Determination of E*/E and ␯* (Equilateral Triangular
Pattern) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Curves for the Determination of E*/E and ␯* (Square Pattern). . . . . . . . . . . . . . .
U-Tube Tubesheet Configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tube Layout Perimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fixed Tubesheet Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Zd, Zv, Zw, and Zm Versus Xa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fm Versus Xa (0.0 ≤ Q3 ≤ 0.8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fm Versus Xa (−0.8 ≤ Q3 ≤ 0.0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shell With Increased Thickness Adjacent to the Tubesheets . . . . . . . . . . . . . . . . .
Floating Tubesheet Heat Exchangers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stationary Tubesheet Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Floating Tubesheet Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
279
Figures
UHX-3
UHX-9
UHX-10
UHX-11.1
UHX-11.2
UHX-11.3
UHX-11.4
UHX-12.1
UHX-12.2
UHX-13.1
UHX-13.2
UHX-13.3-1
UHX-13.3-2
UHX-13.4
UHX-14.1
UHX-14.2
UHX-14.3
xx
281
281
283
284
286
287
288
289
294
300
301
302
304
308
309
310
Tables
UHX-13.1
UHX-13.2
UHX-17
UHX-20.2.1-1
UHX-20.2.2-1
UHX-20.2.3-1
UHX-20.2.3-2
UHX-20.2.3-3
Part UIG
Formulas for Determination of Zd, Zv, Zm, Zw, and Fm. . . . . . . . . . . . . . . . . . . . . . .
Formulas for the Determination of Ft,min and Ft,max . . . . . . . . . . . . . . . . . . . . . . . . .
Flanged-and-Flued or Flanged-Only Expansion Joint Load Cases and Stress
Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Summary Table for Steps 7 and 8, Elastic Iteration Tubesheet Results. . . . . . . .
Summary Table for Steps 7 and 8, Tubesheet Results. . . . . . . . . . . . . . . . . . . . . . .
Summary Table for Step 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Summary Table for Steps 7 and 8, Elastic Iteration . . . . . . . . . . . . . . . . . . . . . . . . .
Summary Table for Step 10, Shell and Channel Stress Results. . . . . . . . . . . . . . .
298
299
319
328
330
333
333
334
Requirements for Pressure Vessels Constructed of Impregnated
Graphite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
Nonmandatory Introduction
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
General
UIG-1
UIG-2
UIG-3
Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
Equipment and Service Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
Terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
Materials
UIG-5
UIG-6
UIG-7
UIG-8
Raw Material Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Certified Material Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tolerances for Impregnated Graphite Tubes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
342
342
343
343
343
343
UIG-28
UIG-29
UIG-34
UIG-36
UIG-45
UIG-60
Loadings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Allowable Stress Values for Certified Material . . . . . . . . . . . . . . . . . . .
Thickness of Cylindrical Shells Made of Certified Materials Under Internal
Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Euler Buckling of Extruded Graphite Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Calculating Flat Heads, Covers, and Tubesheets . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Openings and Reinforcements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nozzle Neck Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lethal Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fabrication
UIG-75
UIG-76
UIG-77
UIG-78
UIG-79
UIG-80
UIG-81
UIG-84
General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Procedure and Personnel Qualification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Certified Material Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Certified Cement Specification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Certified Cementing Procedure Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cementing Technician Qualification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair of Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Required Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
352
352
352
353
353
354
354
358
Design
UIG-22
UIG-23
UIG-27
343
344
344
344
346
346
346
Inspection and Tests
UIG-90
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359
UIG-95
Visual Examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359
UIG-96
Qualification of Visual Examination Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359
xxi
UIG-97
UIG-99
UIG-112
UIG-115
UIG-116
UIG-120
UIG-121
UIG-125
Acceptance Standards and Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pressure Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality Control Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Markings and Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Required Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pressure Relief Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
359
359
359
360
360
360
360
360
345
346
346
347
UIG-76-1
UIG-76-2
UIG-76-3
UIG-76-4
UIG-76-5
Typical Graphite Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration G Stationary Tubesheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration G Floating Tubesheet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unacceptable Nozzle Attachment Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Some Acceptable Nozzle Attachment Details in Impregnated Graphite
Pressure Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tension Test Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cement Material Tension Test Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tube to Tubesheet Tension Test Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tube Cement Joint Tension Test Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tube Tension Test Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tables
UIG-6-1
UIG-84-1
Properties of Certified Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343
Test Frequency for Certified Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
Figures
UIG-34-1
UIG-34-2
UIG-34-3
UIG-36-1
UIG-36-2
348
353
354
355
356
357
MANDATORY APPENDICES
1
2
3
4
5
6
7
8
9
10
11
12
13
14
16
17
18
19
20
21
22
Supplementary Design Formulas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rules for Bolted Flange Connections With Ring Type Gaskets . . . . . . . . . . . . . .
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rounded Indications Charts Acceptance Standard for Radiographically
Determined Rounded Indications in Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flanged-and-Flued or Flanged-Only Expansion Joints. . . . . . . . . . . . . . . . . . . . . . .
Methods for Magnetic Particle Examination (MT) . . . . . . . . . . . . . . . . . . . . . . . . . .
Examination of Steel Castings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Methods for Liquid Penetrant Examination (PT). . . . . . . . . . . . . . . . . . . . . . . . . . . .
Jacketed Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quality Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Capacity Conversions for Safety Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ultrasonic Examination of Welds (UT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vessels of Noncircular Cross Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Integral Flat Heads With a Large, Single, Circular, Centrally Located
Opening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Submittal of Technical Inquiries to the Boiler and Pressure Vessel
Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dimpled or Embossed Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adhesive Attachment of Nameplates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrically Heated or Gas Fired Jacketed Steam Kettles . . . . . . . . . . . . . . . . . . . .
Hubs Machined From Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Jacketed Vessels Constructed of Work-Hardened Nickel . . . . . . . . . . . . . . . . . . . .
Integrally Forged Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xxii
373
394
416
419
428
431
433
436
438
447
450
454
455
495
502
504
514
515
516
517
518
23
24
25
26
27
28
30
31
32
33
34
35
36
37
38
39
40
External Pressure Design of Copper, Copper Alloy, and Titanium Alloy
Condenser and Heat Exchanger Tubes With Integral Fins . . . . . . . . . . . . . . . . .
Design Rules for Clamp Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acceptance of Testing Laboratories and Authorized Observers for
Capacity Certification of Pressure Relief Valves . . . . . . . . . . . . . . . . . . . . . . . . .
Bellows Expansion Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alternative Requirements for Glass-Lined Vessels . . . . . . . . . . . . . . . . . . . . . . . . . .
Alternative Corner Weld Joint Detail for Box Headers for Air-Cooled Heat
Exchangers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rules for Drilled Holes Not Penetrating Through Vessel Wall . . . . . . . . . . . . . . .
Rules for Cr–Mo Steels With Additional Requirements for Welding and Heat
Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Local Thin Areas in Cylindrical Shells and in Spherical Segments of
Shells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standards Units for Use in Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Requirements for Use of High Silicon Stainless Steels for Pressure
Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rules for Mass-Production of Pressure Vessels. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standard Test Method for Determining the Flexural Strength of Certified
Materials Using Three-Point Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standard Test Method for Determining the Tensile Strength of Certified
Impregnated Graphite Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standard Test Method for Compressive Strength of Impregnated Graphite . . . .
Testing the Coefficient of Permeability of Impregnated Graphite . . . . . . . . . . . . .
Thermal Expansion Test Method for Graphite and Impregnated Graphite . . . . .
520
522
528
530
556
559
562
564
567
570
571
573
576
578
580
582
584
NONMANDATORY APPENDICES
A
C
D
E
F
G
H
K
L
M
P
R
S
T
W
Y
DD
EE
FF
GG
HH
Basis for Establishing Allowable Loads for Tube-to-Tubesheet Joints . . . . . . . .
Suggested Methods for Obtaining the Operating Temperature of Vessel Walls
in Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Suggested Good Practice Regarding Internal Structures . . . . . . . . . . . . . . . . . . . . .
Suggested Good Practice Regarding Corrosion Allowance. . . . . . . . . . . . . . . . . . .
Suggested Good Practice Regarding Linings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Suggested Good Practice Regarding Piping Reactions and Design of Supports
and Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Guidance to Accommodate Loadings Produced by Deflagration. . . . . . . . . . . . . .
Sectioning of Welded Joints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Examples Illustrating the Application of Code Formulas and Rules . . . . . . . . . .
Installation and Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Basis for Establishing Allowable Stress Values for UCI, UCD, and ULT
Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preheating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Design Considerations for Bolted Flange Connections . . . . . . . . . . . . . . . . . . . . . .
Temperature Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Guide for Preparing Manufacturer’s Data Reports . . . . . . . . . . . . . . . . . . . . . . . . . .
Flat Face Flanges With Metal-to-Metal Contact Outside the Bolt Circle . . . . . .
Guide to Information Appearing on Certificate of Authorization (See
Fig. DD-1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Half-Pipe Jackets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Guide for the Design and Operation of Quick-Actuating (Quick-Opening)
Closures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Guidance for the Use of U.S. Customary and SI Units in the ASME
Boiler and Pressure Vessel Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tube Expanding Procedures and Qualification . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xxiii
587
593
594
595
596
597
599
601
603
652
658
659
661
663
664
683
696
699
704
707
710
JJ
KK
LL
MM
Index
Flowcharts Illustrating Impact Testing Requirements and Exemptions
From Impact Testing by the Rules of UHA-51. . . . . . . . . . . . . . . . . . . . . . . . . . .
Guide for Preparing User’s Design Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . .
Graphical Representations of Ft,min and Ft,max . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alternative Marking and Stamping of Graphite Pressure Vessels . . . . . . . . . . . . .
720
727
733
736
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 737
xxiv
2010 ASME
BOILER AND PRESSURE VESSEL CODE
SECTIONS
I
Rules for Construction of Power Boilers
II
Materials
Part A — Ferrous Material Specifications
Part B — Nonferrous Material Specifications
Part C — Specifications for Welding Rods, Electrodes, and Filler Metals
Part D — Properties (Customary)
Part D — Properties (Metric)
III
Rules for Construction of Nuclear Facility Components
Subsection NCA — General Requirements for Division 1 and Division 2
Division 1
Subsection NB — Class 1 Components
Subsection NC — Class 2 Components
Subsection ND — Class 3 Components
Subsection NE — Class MC Components
Subsection NF — Supports
Subsection NG — Core Support Structures
Subsection NH — Class 1 Components in Elevated Temperature Service
Appendices
Division 2 — Code for Concrete Containments
Division 3 — Containments for Transportation and Storage of Spent Nuclear Fuel
and High Level Radioactive Material and Waste
IV
Rules for Construction of Heating Boilers
V
Nondestructive Examination
VI
Recommended Rules for the Care and Operation of Heating Boilers
VII
Recommended Guidelines for the Care of Power Boilers
VIII
Rules for Construction of Pressure Vessels
Division 1
Division 2 — Alternative Rules
Division 3 — Alternative Rules for Construction of High Pressure Vessels
IX
Welding and Brazing Qualifications
X
Fiber-Reinforced Plastic Pressure Vessels
XI
Rules for Inservice Inspection of Nuclear Power Plant Components
XII
Rules for Construction and Continued Service of Transport Tanks
xxv
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ADDENDA
and 2, will be included with the update service to Subsection NCA.
Interpretations of the Code are posted in January and
July at www.cstools.asme.org/interpretations.
Addenda, which include additions and revisions to individual Sections of the Code, will be sent automatically to
purchasers of the applicable Sections up to the publication
of the 2013 Code. The 2010 Code is available only in the
loose-leaf format; accordingly, the Addenda will be issued
in the loose-leaf, replacement-page format.
CODE CASES
The Boiler and Pressure Vessel Committee meets regularly to consider proposed additions and revisions to the
Code and to formulate Cases to clarify the intent of existing
requirements or provide, when the need is urgent, rules
for materials or constructions not covered by existing Code
rules. Those Cases that have been adopted will appear
in the appropriate 2010 Code Cases book: “Boilers and
Pressure Vessels” and “Nuclear Components.” Supplements will be sent automatically to the purchasers of the
Code Cases books up to the publication of the 2013 Code.
INTERPRETATIONS
ASME issues written replies to inquiries concerning
interpretation of technical aspects of the Code. The Interpretations for each individual Section will be published
separately and will be included as part of the update service
to that Section. Interpretations of Section III, Divisions 1
xxvi
FOREWORD
The American Society of Mechanical Engineers set up a
committee in 1911 for the purpose of formulating standard
rules for the construction of steam boilers and other pressure vessels. This committee is now called the Boiler and
Pressure Vessel Committee.
The Committee’s function is to establish rules of safety,
relating only to pressure integrity, governing the construction 1 of boilers, pressure vessels, transport tanks and
nuclear components, and inservice inspection for pressure
integrity of nuclear components and transport tanks, and
to interpret these rules when questions arise regarding their
intent. This code does not address other safety issues relating to the construction of boilers, pressure vessels, transport
tanks and nuclear components, and the inservice inspection
of nuclear components and transport tanks. The user of
the Code should refer to other pertinent codes, standards,
laws, regulations, or other relevant documents. With few
exceptions, the rules do not, of practical necessity, reflect
the likelihood and consequences of deterioration in service
related to specific service fluids or external operating environments. Recognizing this, the Committee has approved
a wide variety of construction rules in this Section to allow
the user or his designee to select those which will provide
a pressure vessel having a margin for deterioration in service so as to give a reasonably long, safe period of usefulness. Accordingly, it is not intended that this Section
be used as a design handbook; rather, engineering judgment
must be employed in the selection of those sets of Code
rules suitable to any specific service or need.
This Code contains mandatory requirements, specific
prohibitions, and nonmandatory guidance for construction
activities. The Code does not address all aspects of these
activities and those aspects which are not specifically
addressed should not be considered prohibited. The Code
is not a handbook and cannot replace education, experience, and the use of engineering judgment. The phrase
engineering judgment refers to technical judgments made
by knowledgeable designers experienced in the application
of the Code. Engineering judgments must be consistent
with Code philosophy and such judgments must never
be used to overrule mandatory requirements or specific
prohibitions of the Code.
1
Construction, as used in this Foreword, is an all-inclusive term comprising materials, design, fabrication, examination, inspection, testing,
certification, and pressure relief.
The Committee recognizes that tools and techniques
used for design and analysis change as technology progresses and expects engineers to use good judgment in the
application of these tools. The designer is responsible for
complying with Code rules and demonstrating compliance
with Code equations when such equations are mandatory.
The Code neither requires nor prohibits the use of computers for the design or analysis of components constructed
to the requirements of the Code. However, designers and
engineers using computer programs for design or analysis
are cautioned that they are responsible for all technical
assumptions inherent in the programs they use and they
are responsible for the application of these programs to
their design.
The Code does not fully address tolerances. When
dimensions, sizes, or other parameters are not specified
with tolerances, the values of these parameters are considered nominal and allowable tolerances or local variances
may be considered acceptable when based on engineering
judgment and standard practices as determined by the
designer.
The Boiler and Pressure Vessel Committee deals with
the care and inspection of boilers and pressure vessels in
service only to the extent of providing suggested rules of
good practice as an aid to owners and their inspectors.
The rules established by the Committee are not to be
interpreted as approving, recommending, or endorsing any
proprietary or specific design or as limiting in any way the
manufacturer’s freedom to choose any method of design
or any form of construction that conforms to the Code rules.
The Boiler and Pressure Vessel Committee meets regularly to consider revisions of the rules, new rules as dictated
by technological development, Code Cases, and requests
for interpretations. Only the Boiler and Pressure Vessel
Committee has the authority to provide official interpretations of this Code. Requests for revisions, new rules, Code
Cases, or interpretations shall be addressed to the Secretary
in writing and shall give full particulars in order to receive
consideration and action (see Mandatory Appendix covering preparation of technical inquiries). Proposed revisions to the Code resulting from inquiries will be presented
to the Main Committee for appropriate action. The action
of the Main Committee becomes effective only after confirmation by letter ballot of the Committee and approval
by ASME.
xxvii
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Proposed revisions to the Code approved by the Committee are submitted to the American National Standards Institute and published at http://cstools.asme.org/csconnect/
public/index.cfm?PublicReviewpRevisions to invite comments from all interested persons. After the allotted time
for public review and final approval by ASME, revisions
are published in updates to the Code.
Code Cases may be used in the construction of components to be stamped with the ASME Code symbol beginning with the date of their approval by ASME.
After Code revisions are approved by ASME, they may
be used beginning with the date of issuance. Revisions,
except for revisions to material specifications in Section
II, Parts A and B, become mandatory six months after such
date of issuance, except for boilers or pressure vessels
contracted for prior to the end of the six-month period.
Revisions to material specifications are originated by the
American Society for Testing and Materials (ASTM) and
other recognized national or international organizations,
and are usually adopted by ASME. However, those revisions may or may not have any effect on the suitability of
material, produced to earlier editions of specifications, for
use in ASME construction. ASME material specifications
approved for use in each construction Code are listed in
the Guidelines for Acceptable ASTM Editions and in the
Guidelines for Acceptable Non-ASTM Editions, in Section
II, Parts A and B. These Guidelines list, for each specification, the latest edition adopted by ASME, and earlier and
later editions considered by ASME to be identical for
ASME construction.
The Boiler and Pressure Vessel Committee in the formulation of its rules and in the establishment of maximum
design and operating pressures considers materials, construction, methods of fabrication, inspection, and safety
devices.
The Code Committee does not rule on whether a component shall or shall not be constructed to the provisions of
the Code. The Scope of each Section has been established
to identify the components and parameters considered by
the Committee in formulating the Code rules.
Questions or issues regarding compliance of a specific
component with the Code rules are to be directed to the
ASME Certificate Holder (Manufacturer). Inquiries concerning the interpretation of the Code are to be directed
to the ASME Boiler and Pressure Vessel Committee.
ASME is to be notified should questions arise concerning
improper use of an ASME Code symbol.
The specifications for materials given in Section II are
identical with or similar to those of specifications published
by ASTM, AWS, and other recognized national or international organizations. When reference is made in an ASME
material specification to a non-ASME specification for
which a companion ASME specification exists, the reference shall be interpreted as applying to the ASME material
specification. Not all materials included in the material
specifications in Section II have been adopted for Code
use. Usage is limited to those materials and grades adopted
by at least one of the other Sections of the Code for application under rules of that Section. All materials allowed by
these various Sections and used for construction within the
scope of their rules shall be furnished in accordance with
material specifications contained in Section II or referenced
in the Guidelines for Acceptable Editions in Section II,
Parts A and B, except where otherwise provided in Code
Cases or in the applicable Section of the Code. Materials
covered by these specifications are acceptable for use in
items covered by the Code Sections only to the degree
indicated in the applicable Section. Materials for Code use
should preferably be ordered, produced, and documented
on this basis; Guidelines for Acceptable Editions in
Section II, Part A and Guidelines for Acceptable Editions
in Section II, Part B list editions of ASME and year dates
of specifications that meet ASME requirements and which
may be used in Code construction. Material produced to
an acceptable specification with requirements different
from the requirements of the corresponding specifications
listed in the Guidelines for Acceptable Editions in Part A
or Part B may also be used in accordance with the above,
provided the material manufacturer or vessel manufacturer
certifies with evidence acceptable to the Authorized Inspector that the corresponding requirements of specifications
listed in the Guidelines for Acceptable Editions in Part A
or Part B have been met. Material produced to an acceptable
material specification is not limited as to country of origin.
When required by context in this Section, the singular
shall be interpreted as the plural, and vice-versa; and the
feminine, masculine, or neuter gender shall be treated as
such other gender as appropriate.
xxviii
STATEMENT OF POLICY
ON THE USE OF CODE SYMBOLS AND
CODE AUTHORIZATION IN ADVERTISING
ASME has established procedures to authorize qualified
organizations to perform various activities in accordance
with the requirements of the ASME Boiler and Pressure
Vessel Code. It is the aim of the Society to provide recognition of organizations so authorized. An organization holding authorization to perform various activities in
accordance with the requirements of the Code may state
this capability in its advertising literature.
Organizations that are authorized to use Code Symbols
for marking items or constructions that have been constructed and inspected in compliance with the ASME Boiler
and Pressure Vessel Code are issued Certificates of Authorization. It is the aim of the Society to maintain the standing
of the Code Symbols for the benefit of the users, the
enforcement jurisdictions, and the holders of the symbols
who comply with all requirements.
Based on these objectives, the following policy has been
established on the usage in advertising of facsimiles of the
symbols, Certificates of Authorization, and reference to
Code construction. The American Society of Mechanical
Engineers does not “approve,” “certify,” “rate,” or
“endorse” any item, construction, or activity and there shall
be no statements or implications that might so indicate. An
organization holding a Code Symbol and/or a Certificate of
Authorization may state in advertising literature that items,
constructions, or activities “are built (produced or performed) or activities conducted in accordance with the
requirements of the ASME Boiler and Pressure Vessel
Code,” or “meet the requirements of the ASME Boiler and
Pressure Vessel Code.” An ASME corporate logo shall not
be used by any organization other than ASME.
The ASME Symbol shall be used only for stamping and
nameplates as specifically provided in the Code. However,
facsimiles may be used for the purpose of fostering the
use of such construction. Such usage may be by an association or a society, or by a holder of a Code Symbol who
may also use the facsimile in advertising to show that
clearly specified items will carry the symbol. General usage
is permitted only when all of a manufacturer’s items are
constructed under the rules.
STATEMENT OF POLICY
ON THE USE OF ASME MARKING
TO IDENTIFY MANUFACTURED ITEMS
The ASME Boiler and Pressure Vessel Code provides
rules for the construction of boilers, pressure vessels, and
nuclear components. This includes requirements for materials, design, fabrication, examination, inspection, and
stamping. Items constructed in accordance with all of the
applicable rules of the Code are identified with the official
Code Symbol Stamp described in the governing Section
of the Code.
Markings such as “ASME,” “ASME Standard,” or any
other marking including “ASME” or the various Code
Symbols shall not be used on any item that is not constructed in accordance with all of the applicable requirements of the Code.
Items shall not be described on ASME Data Report
Forms nor on similar forms referring to ASME that tend
to imply that all Code requirements have been met when,
in fact, they have not been. Data Report Forms covering
items not fully complying with ASME requirements should
not refer to ASME or they should clearly identify all exceptions to the ASME requirements.
xxix
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PERSONNEL
ASME Boiler and Pressure Vessel Standards Committees,
Subgroups, and Working Groups
As of January 1, 2010
TECHNICAL OVERSIGHT MANAGEMENT COMMITTEE (TOMC)
J. G. Feldstein, Chair
T. P. Pastor, Vice Chair
J. S. Brzuszkiewicz, Staff
Secretary
R. W. Barnes
R. J. Basile
J. E. Batey
D. L. Berger
M. N. Bressler
D. A. Canonico
R. P. Deubler
D. A. Douin
D. Eisberg
R. E. Gimple
M. Gold
T. E. Hansen
MARINE CONFERENCE GROUP
J. F. Henry
C. L. Hoffmann
G. G. Karcher
W. M. Lundy
J. R. MacKay
U. R. Miller
P. A. Molvie
W. E. Norris
G. C. Park
M. D. Rana
B. W. Roberts
S. C. Roberts
F. J. Schaaf, Jr.
A. Selz
R. W. Swayne
H. N. Patel, Chair
J. G. Hungerbuhler, Jr.
CONFERENCE COMMITTEE
R. J. Aben, Jr. — Michigan
(Chair)
R. D. Reetz — North Dakota
(Vice Chair)
D. A. Douin — Ohio
(Secretary)
J. S. Aclaro — California
J. T. Amato — Minnesota
B. P. Anthony — Rhode Island
R. D. Austin — Arizona
E. W. Bachellier — Nunavut,
Canada
B. F. Bailey — Illinois
J. E. Bell — Michigan
W. K. Brigham — New
Hampshire
M. A. Burns — Florida
J. H. Burpee — Maine
C. B. Cantrell — Nebraska
D. C. Cook — California
J. A. Davenport —
Pennsylvania
S. Donovan — Northwest
Territories, Canada
D. Eastman — Newfoundland
and Labrador, Canada
E. Everett — Georgia
C. Fulton — Alaska
J. M. Given, Jr. — North
Carolina
M. Graham — Oregon
R. J. Handy — Kentucky
J. B. Harlan — Delaware
E. G. Hilton — Virginia
K. Hynes — Prince Edward
Island, Canada
D. T. Jagger — Ohio
D. J. Jenkins — Kansas
A. P. Jones — Texas
E. S. Kawa, Jr. —
Massachusetts
HONORARY MEMBERS (MAIN COMMITTEE)
F. P. Barton
R. J. Cepluch
L. J. Chockie
T. M. Cullen
W. D. Doty
J. R. Farr
G. E. Feigel
R. C. Griffin
O. F. Hedden
E. J. Hemzy
M. H. Jawad
A. J. Justin
W. G. Knecht
J. LeCoff
T. G. McCarty
G. C. Millman
R. A. Moen
R. F. Reedy
K. K. Tam
L. P. Zick, Jr.
ADMINISTRATIVE COMMITTEE
J. S. Brzuszkiewicz, Staff
Secretary
R. W. Barnes
J. E. Batey
D. L. Berger
D. Eisberg
J. G. Feldstein
J. F. Henry
P. A. Molvie
G. C. Park
T. P. Pastor
A. Selz
HONORS AND AWARDS COMMITTEE
M. Gold, Chair
F. E. Gregor, Vice Chair
T. Schellens, Staff Secretary
D. R. Sharp, Staff Secretary
R. J. Basile
J. E. Batey
D. L. Berger
J. G. Feldstein
G. Pallichadath
J. D. Reynolds
W. L. Haag, Jr.
S. F. Harrison, Jr.
R. M. Jessee
W. C. LaRochelle
T. P. Pastor
A. Selz
R. R. Stevenson
xxx
M. R. Klosterman — Iowa
M. Kotb — Quebec, Canada
K. J. Kraft — Maryland
B. Krasiun — Saskatchewan,
Canada
K. T. Lau — Alberta, Canada
G. Lemay — Ontario, Canada
W. McGivney — New York
T. J. Monroe — Oklahoma
G. R. Myrick — Arkansas
S. V. Nelson — Colorado
W. R. Owens — Louisiana
R. P. Pate — Alabama
R. L. Perry — Nevada
H. D. Pfaff — South Dakota
A. E. Platt — Connecticut
J. F. Porcella — West Virginia
M. R. Poulin — Idaho
D. C. Price — Yukon
Territory, Canada
R. S. Pucek — Wisconsin
T. W. Rieger — Manitoba,
Canada
A. E. Rogers — Tennessee
D. E. Ross — New Brunswick,
Canada
K. A. Rudolph — Hawaii
M. J. Ryan — Illinois
G. Scribner — Missouri
J. G. Siggers — British
Columbia, Canada
T. Stewart — Montana
R. K. Sturm — Utah
M. J. Verhagen — Wisconsin
P. L. Vescio, Jr. — New York
M. Washington — New Jersey
K. L. Watson — Mississippi
L. Williamson — Washington
D. J. Willis — Indiana
INTERNATIONAL INTEREST REVIEW GROUP
V. Felix
Y.-G. Kim
S. H. Leong
W. Lin
O. F. Manafa
Subgroup on Fabrication and Examination (BPV I)
J. T. Pillow, Chair
C. T. McDaris
G. W. Galanes, Secretary
T. C. McGough
J. L. Arnold
R. E. McLaughlin
D. L. Berger
Y. Oishi
S. W. Cameron
J. P. Swezy, Jr.
J. Hainsworth
R. V. Wielgoszinski
T. E. Hansen
Subgroup on General Requirements (BPV I)
R. E. McLaughlin, Chair
J. T. Pillow
F. Massi, Secretary
D. Tompkins
P. D. Edwards
S. V. Torkildson
T. E. Hansen
D. E. Tuttle
W. L. Lowry
R. V. Wielgoszinski
T. C. McGough
D. J. Willis
E. M. Ortman
Subgroup on Materials (BPV I)
B. W. Roberts, Chair
K. L. Hayes
J. S. Hunter, Secretary
J. F. Henry
S. H. Bowes
O. X. Li
D. A. Canonico
J. R. MacKay
K. K. Coleman
F. Masuyama
P. Fallouey
D. W. Rahoi
G. W. Galanes
J. M. Tanzosh
Subgroup on Piping (BPV I)
T. E. Hansen, Chair
W. L. Lowry
D. L. Berger
F. Massi
P. D. Edwards
T. C. McGough
G. W. Galanes
D. Tompkins
T. G. Kosmatka
E. A. Whittle
Subgroup on Heat Recovery Steam Generators (BPV I)
T. E. Hansen, Chair
E. M. Ortman
D. Dziubinski, Secretary
R. D. Schueler, Jr.
L. R. Douglas
J. C. Steverman, Jr.
J. Gertz
D. Tompkins
G. B. Komora
S. V. Torkildson
C. T. McDaris
B. C. Turczynski
B. W. Moore
COMMITTEE ON MATERIALS (II)
J. F. Henry, Chair
R. C. Sutherlin
M. Gold, Vice Chair
R. W. Swindeman
N. Lobo, Staff Secretary
J. M. Tanzosh
F. Abe
B. E. Thurgood
A. Appleton
D. Kwon, Delegate
M. N. Bressler
O. Oldani, Delegate
H. D. Bushfield
W. R. Apblett, Jr., Contributing
J. Cameron
Member
D. A. Canonico
E. G. Nisbett, Contributing
A. Chaudouet
Member
P. Fallouey
E. Upitis, Contributing
J. R. Foulds
Member
D. W. Gandy
T. M. Cullen, Honorary
M. H. Gilkey
Member
J. F. Grubb
W. D. Doty, Honorary
C. L. Hoffmann
Member
M. Katcher
W. D. Edsall, Honorary
P. A. Larkin
Member
F. Masuyama
G. C. Hsu, Honorary Member
R. K. Nanstad
R. A. Moen, Honorary
M. L. Nayyar
Member
D. W. Rahoi
C. E. Spaeder, Jr., Honorary
B. W. Roberts
Member
E. Shapiro
A. W. Zeuthen, Honorary
M. H. Skillingberg
Member
C. Minu
Y.-W. Park
R. Reynaga
P. Williamson
PROJECT TEAM ON HYDROGEN TANKS
M. D. Rana, Chair
A. P. Amato, Staff Secretary
F. L. Brown
D. A. Canonico
D. C. Cook
J. Coursen
J. W. Felbaum
B. D. Hawkes
N. L. Newhouse
A. S. Olivares
G. B. Rawls, Jr.
B. F. Shelley
J. R. Sims, Jr.
N. Sirosh
J. H. Smith
S. Staniszewski
R. Subramanian
T. Tahara
D. W. Treadwell
E. Upitis
Y. Wada
C. T. I. Webster
R. C. Biel, Contributing
Member
J. Birdsall, Contributing
Member
M. Duncan, Contributing
Member
D. R. Frikken, Contributing
Member
L. E. Hayden, Jr., Contributing
Member
K. T. Lau, Contributing
Member
K. Oyamada, Contributing
Member
C. H. Rivkin, Contributing
Member
C. San Marchi, Contributing
Member
B. Somerday, Contributing
Member
COMMITTEE ON POWER BOILERS (I)
D. L. Berger, Chair
R. E. McLaughlin, Vice Chair
U. D’Urso, Staff Secretary
J. L. Arnold
S. W. Cameron
D. A. Canonico
K. K. Coleman
P. D. Edwards
P. Fallouey
J. G. Feldstein
G. W. Galanes
T. E. Hansen
J. F. Henry
J. S. Hunter
W. L. Lowry
J. R. MacKay
F. Massi
T. C. McGough
P. A. Molvie
Y. Oishi
J. T. Pillow
B. W. Roberts
R. D. Schueler, Jr.
J. P. Swezy, Jr.
J. M. Tanzosh
R. V. Wielgoszinski
D. J. Willis
G. Ardizzoia, Delegate
H. Michael, Delegate
E. M. Ortman, Alternate
D. N. French, Honorary
Member
R. L. Williams, Honorary
Member
Subgroup on Design (BPV I)
P. A. Molvie, Chair
J. Vattappilly, Secretary
D. I. Anderson
P. Dhorajia
J. P. Glaspie
G. B. Komora
J. C. Light
B. W. Moore
R. D. Schueler, Jr.
J. L. Seigle
J. P. Swezy, Jr.
S. V. Torkildson
G. Ardizzoia, Delegate
xxxi
Subgroup on External Pressure (BPV II)
R. W. Mikitka, Chair
J. A. A. Morrow, Secretary
L. F. Campbell
D. S. Griffin
J. F. Grubb
J. R. Harris III
M. Katcher
D. L. Kurle
C. R. Thomas
C. H. Sturgeon, Contributing
Member
Subgroup on Strength of Weldments (BPV II & BPV IX)
J. M. Tanzosh, Chair
W. F. Newell, Jr., Secretary
S. H. Bowes
K. K. Coleman
P. D. Flenner
J. R. Foulds
D. W. Gandy
K. L. Hayes
J. F. Henry
D. W. Rahoi
B. W. Roberts
J. P. Shingledecker
W. J. Sperko
B. E. Thurgood
Subgroup on Ferrous Specifications (BPV II)
A. Appleton, Chair
R. M. Davison
B. M. Dingman
M. J. Dosdourian
P. Fallouey
T. Graham
J. F. Grubb
K. M. Hottle
D. S. Janikowski
D. C. Krouse
L. J. Lavezzi
W. C. Mack
J. K. Mahaney
R. J. Marciniec
A. S. Melilli
E. G. Nisbett
K. E. Orie
J. Shick
E. Upitis
R. Zawierucha
Subgroup on International Material Specifications (BPV II)
A. Chaudouet, Chair
D. Dziubinski, Secretary
S. W. Cameron
D. A. Canonico
P. Fallouey
A. F. Garbolevsky
D. O. Henry
M. Ishikawa
O. X. Li
W. M. Lundy
A. R. Nywening
R. D. Schueler, Jr.
E. Upitis
D. Kwon, Delegate
O. Oldani, Delegate
H. Lorenz, Contributing
Member
Subgroup on Strength, Ferrous Alloys (BPV II)
C. L. Hoffmann, Chair
J. M. Tanzosh, Secretary
F. Abe
W. R. Apblett, Jr.
D. A. Canonico
A. Di Rienzo
P. Fallouey
J. R. Foulds
M. Gold
J. A. Hall
J. F. Henry
K. Kimura
F. Masuyama
S. Matsumoto
H. Murakami
D. W. Rahoi
B. W. Roberts
M. S. Shelton
J. P. Shingledecker
M. J. Slater
R. W. Swindeman
B. E. Thurgood
T. P. Vassallo, Jr.
Subgroup on Nonferrous Alloys (BPV II)
M. Katcher, Chair
R. C. Sutherlin, Secretary
W. R. Apblett, Jr.
M. H. Gilkey
J. F. Grubb
A. Heino
J. Kissell
P. A. Larkin
T. M. Malota
S. Matsumoto
H. Matsuo
J. A. McMaster
D. W. Rahoi
E. Shapiro
M. H. Skillingberg
D. Tyler
R. Zawierucha
H. D. Bushfield, Contributing
Member
Special Working Group on Nonmetallic Materials (BPV II)
C. W. Rowley, Chair
F. L. Brown
S. R. Frost
M. Golliet
COMMITTEE ON CONSTRUCTION OF NUCLEAR FACILITY
COMPONENTS (III)
R. W. Barnes, Chair
R. M. Jessee, Vice Chair
C. A. Sanna, Staff Secretary
W. H. Borter
M. N. Bressler
T. D. Burchell
J. R. Cole
R. P. Deubler
B. A. Erler
G. M. Foster
R. S. Hill III
C. L. Hoffmann
V. Kostarev
W. C. LaRochelle
K. A. Manoly
W. N. McLean
M. N. Mitchell
D. K. Morton
R. F. Reedy
J. D. Stevenson
K. R. Wichman
C. S. Withers
Y. H. Choi, Delegate
T. Ius, Delegate
C. C. Kim, Contributing
Member
E. B. Branch, Honorary
Member
G. D. Cooper, Honorary
Member
W. D. Doty, Honorary
Member
D. F. Landers, Honorary
Member
R. A. Moen, Honorary
Member
C. J. Pieper, Honorary
Member
Subgroup on Containment Systems for Spent Fuel
and High-Level Waste Transport Packagings (BPV III)
G. M. Foster, Chair
G. J. Solovey, Vice Chair
D. K. Morton, Secretary
D. J. Ammerman
W. G. Beach
G. Bjorkman
W. H. Borter
G. R. Cannell
E. L. Farrow
R. S. Hill III
S. Horowitz
D. W. Lewis
C. G. May
Subgroup on Physical Properties (BPV II)
J. F. Grubb, Chair
H. D. Bushfield
P. S. Hill
M. R. Kessler
F. Worth
P. Fallouey
E. Shapiro
xxxii
P. E. McConnell
I. D. McInnes
A. B. Meichler
R. E. Nickell
E. L. Pleins
T. Saegusa
H. P. Shrivastava
N. M. Simpson
R. H. Smith
J. D. Stevenson
C. J. Temus
A. D. Watkins
Subgroup on Design (BPV III)
R. P. Deubler, Chair
R. S. Hill III, Vice Chair
A. N. Nguyen, Secretary
T. M. Adams
S. Asada
M. N. Bressler
C. W. Bruny
J. R. Cole
R. E. Cornman, Jr.
A. A. Dermenjian
P. Hirschberg
R. I. Jetter
R. B. Keating
J. F. Kielb
H. Kobayashi
D. F. Landers
K. A. Manoly
R. J. Masterson
W. N. McLean
J. C. Minichiello
M. Morishita
E. L. Pleins
I. Saito
G. C. Slagis
J. D. Stevenson
J. P. Tucker
K. R. Wichman
J. Yang
T. Ius, Delegate
Working Group on Piping (SG-D) (BPV III)
P. Hirschberg, Chair
G. Z. Tokarski, Secretary
T. M. Adams
G. A. Antaki
C. Basavaraju
J. Catalano
J. R. Cole
M. A. Gray
R. W. Haupt
J. Kawahata
R. B. Keating
V. Kostarev
Y. Liu
J. F. McCabe
J. C. Minichiello
Working Group on Probabilistic Methods in Design
(SG-D) (BPV III)
Working Group on Supports (SG-D) (BPV III)
R. J. Masterson, Chair
F. J. Birch, Secretary
K. Avrithi
U. S. Bandyopadhyay
R. P. Deubler
W. P. Golini
A. N. Nguyen
I. Saito
J. R. Stinson
T. G. Terryah
G. Z. Tokarski
C.-I. Wu
Working Group on Core Support Structures (SG-D) (BPV III)
J. Yang, Chair
J. F. Kielb, Secretary
F. G. Al-Chammas
J. T. Land
H. S. Mehta
J. F. Mullooly
A. Tsirigotis
Working Group on Design Methodology (SG-D) (BPV III)
R. B. Keating, Chair
S. D. Snow, Secretary
K. Avrithi
M. Basol
D. L. Caldwell
H. T. Harrison III
P. Hirschberg
H. Kobayashi
H. Lockert
J. F. McCabe
A. N. Nguyen
D. H. Roarty
E. A. Rodriguez
J. D. Stevenson
A. Tsirigotis
T. M. Wiger
J. Yang
D. F. Landers, Corresponding
Member
M. K. Au-Yang, Contributing
Member
R. D. Blevins, Contributing
Member
W. S. Lapay, Contributing
Member
Working Group on Design of Division 3 Containments
(SG-D) (BPV III)
E. L. Pleins, Chair
D. J. Ammerman
G. Bjorkman
S. Horowitz
D. W. Lewis
J. C. Minichiello
D. K. Morton
H. P. Shrivastava
C. J. Temus
I. D. McInnes, Contributing
Member
R. E. Nickell, Contributing
Member
E. R. Nelson
A. N. Nguyen
N. J. Shah
M. S. Sills
G. C. Slagis
N. C. Sutherland
E. A. Wais
C.-I. Wu
D. F. Landers, Corresponding
Member
R. D. Patel, Contributing
Member
E. C. Rodabaugh, Contributing
Member
R. S. Hill III, Chair
T. Asayama
K. Avrithi
B. M. Ayyub
A. A. Dermenjian
M. R. Graybeal
D. O. Henry
S. D. Kulat
A. McNeill III
M. Morishita
P. J. O’Regan
N. A. Palm
I. Saito
M. E. Schmidt
A. Tsirigotis
J. P. Tucker
R. M. Wilson
Working Group on Pumps (SG-D) (BPV III)
R. E. Cornman, Jr., Chair
P. W. Behnke
M. D. Eftychiou
A. Fraser
R. Ghanbari
M. Higuchi
C. J. Jerz
R. A. Ladefian
J. W. Leavitt
R. A. Patrick
J. R. Rajan
R. Udo
A. G. Washburn
Working Group on Valves (SG-D) (BPV III)
J. P. Tucker, Chair
G. A. Jolly
W. N. McLean
T. A. McMahon
C. A. Mizer
J. O’Callaghan
J. D. Page
S. N. Shields
H. R. Sonderegger
J. C. Tsacoyeanes
Working Group on Vessels (SG-D) (BPV III)
G. K. Miller, Secretary
C. Basavaraju
C. W. Bruny
J. V. Gregg
W. J. Heilker
A. Kalnins
R. B. Keating
O.-S. Kim
K. Matsunaga
D. E. Matthews
C. Turylo
W. F. Weitze
R. M. Wilson
Special Working Group on Environmental Effects (SG-D) (BPV III)
W. Z. Novak, Chair
R. S. Hill III
xxxiii
C. L. Hoffmann
Y. H. Choi, Delegate
Subgroup on General Requirements (BPV III & 3C)
W. C. LaRochelle, Chair
L. M. Plante, Secretary
A. Appleton
J. R. Berry
J. V. Gardiner
W. P. Golini
G. L. Hollinger
E. A. Mayhew
R. P. McIntyre
M. R. Minick
B. B. Scott
C. T. Smith
W. K. Sowder, Jr.
D. M. Vickery
D. V. Walshe
C. S. Withers
H. Michael, Delegate
Working Group on Duties and Responsibilities (SG-GR) (BPV III)
J. V. Gardiner, Chair
G. L. Hollinger, Secretary
J. R. Berry
M. E. Jennings
K. A. Kavanagh
A. T. Keim
M. A. Lockwood
L. M. Plante
D. J. Roszman
S. Scardigno
Working Group on Quality Assurance, Certification, and
Stamping (SG-GR) (BPV III)
C. T. Smith, Chair
C. S. Withers, Secretary
A. Appleton
B. K. Bobo
S. M. Goodwin
J. W. Highlands
R. P. McIntyre
M. R. Minick
R. B. Patel
S. J. Salvador
W. K. Sowder, Jr.
M. F. Sullivan
G. E. Szabatura
D. M. Vickery
Subgroup on Materials, Fabrication, and Examination (BPV III)
C. L. Hoffmann, Chair
W. G. Beach
W. H. Borter
G. R. Cannell
R. H. Davis
D. M. Doyle
G. M. Foster
B. D. Frew
G. B. Georgiev
S. E. Gingrich
R. M. Jessee
C. C. Kim
M. Lau
H. Murakami
N. M. Simpson
W. J. Sperko
J. R. Stinson
J. F. Strunk
K. B. Stuckey
A. D. Watkins
H. Michael, Delegate
Subgroup on Pressure Relief (BPV III)
J. F. Ball, Chair
E. M. Petrosky
R. F. Reedy, Chair
W. H. Borter
M. N. Bressler
R. P. Deubler
E. V. Imbro
R. M. Jessee
K. A. Manoly
D. K. Morton
J. Ramirez
R. F. Reedy
C. T. Smith
W. K. Sowder, Jr.
Y. Urabe
B. A. Erler
W. C. LaRochelle
J. D. Stevenson
Special Working Group on Polyethylene Pipe (BPV III)
J. C. Minichiello, Chair
T. M. Adams
W. I. Adams
G. A. Antaki
C. Basavaraju
D. Burwell
J. M. Craig
R. R. Croft
E. L. Farrow
E. M. Focht
M. Golliet
A. N. Haddad
R. S. Hill III
P. Krishnaswamy
E. Lever
E. W. McElroy
D. P. Munson
T. M. Musto
L. J. Petroff
C. W. Rowley
F. J. Schaaf, Jr.
C. T. Smith
H. E. Svetlik
D. M. Vickery
Z. J. Zhou
Working Group on Nuclear High-Temperature
Gas-Cooled Reactors (BPV III)
N. Broom, Chair
T. D. Burchell
M. F. Hessheimer
R. S. Hill III
E. V. Imbro
R. I. Jetter
Y. W. Kim
T. R. Lupold
D. L. Marriott
D. K. Morton
T.-L. Sham
Y. Tachibana
T. Yuhara
Subgroup on Graphite Core Components (BPV III)
T. D. Burchell, Chair
C. A. Sanna, Staff Secretary
R. L. Bratton
S.-H. Chi
M. W. Davies
S. W. Doms
S. F. Duffy
O. Gelineau
G. O. Hayner
A. L. Szeglin
D. G. Thibault
Subgroup on Strategy and Management
(BPV III, Divisions 1 and 2)
R. W. Barnes, Chair
C. A. Sanna, Staff Secretary
B. K. Bobo
N. Broom
J. R. Cole
B. A. Erler
C. M. Faidy
J. M. Helmey
M. F. Hessheimer
R. S. Hill III
Special Working Group on Editing and Review (BPV III)
M. P. Hindley
Y. Katoh
M. N. Mitchell
N. N. Nemeth
T. Oku
T. Shibata
M. Srinivasan
A. G. Steer
S. Yu
Subgroup on Industry Experience for New Plants
(BPV III & BPV XI)
G. M. Foster, Chair
J. T. Lindberg, Chair
H. L. Gustin, Secretary
M. L. Coats
A. A. Dermenjian
J. Fletcher
E. B. Gerlach
H. L. Gustin
D. O. Henry
E. V. Imbro
C. C. Kim
O.-S. Kim
xxxiv
K. Matsunaga
R. E. McLaughlin
A. McNeill III
H. Murakami
R. D. Patel
J. C. Poehler
D. W. Sandusky
R. R. Schaefer
D. M. Swann
E. R. Willis
C. S. Withers
S. M. Yee
Subgroup on Magnetic Confinement Fusion Energy Devices
(BPV III)
W. K. Sowder, Jr., Chair
R. W. Barnes
M. Higuchi
K. H. Jong
K. A. Kavanagh
H.-J. Kim
S. Lee
G. Li
X. Li
D. Roszman
S. J. Salvador
Subgroup on Nuclear High-Temperature Reactors (BPV III)
M. Morishita, Chair
R. I. Jetter, Vice Chair
T.-L. Sham, Secretary
N. Broom
Subgroup on Fatigue Strength (BPV III)
W. J. O’Donnell, Chair
S. A. Adams
G. S. Chakrabarti
T. M. Damiani
P. R. Donavin
R. J. Gurdal
C. F. Heberling II
C. E. Hinnant
P. Hirschberg
G. H. Koo
D. K. Morton
J. E. Nestell
JOINT ACI-ASME COMMITTEE ON
CONCRETE COMPONENTS FOR NUCLEAR SERVICE (BPV 3C)
A. C. Eberhardt, Chair
C. T. Smith, Vice Chair
M. L. Vazquez, Staff Secretary
N. Alchaar
J. F. Artuso
H. G. Ashar
C. J. Bang
B. A. Erler
F. Farzam
P. S. Ghosal
J. Gutierrez
J. K. Harrold
G. A. Harstead
M. F. Hessheimer
T. C. Inman
T. E. Johnson
Working Group on Fusion Energy Devices (BPV III)
W. K. Sowder, Jr., Chair
Working Group on Liquid Metal Reactors (BPV III)
T.-L. Sham, Chair
T. Asayama, Secretary
R. W. Barnes
C. M. Faidy
R. I. Jetter
G. H. Koo
M. Li
S. Majumdar
M. Morishita
J. E. Nestell
Special Working Group on Bolted Flanged Joints (BPV III)
R. W. Mikitka, Chair
G. D. Bibel
W. Brown
W. J. Koves
M. S. Shelton
Subgroup on Design Analysis (BPV III)
G. L. Hollinger, Chair
S. A. Adams
M. R. Breach
R. G. Brown
T. M. Damiani
R. J. Gurdal
B. F. Hantz
C. F. Heberling II
C. E. Hinnant
D. P. Jones
A. Kalnins
W. J. Koves
K. Matsunaga
G. A. Miller
W. D. Reinhardt
D. H. Roarty
G. Sannazzaro
T. G. Seipp
G. Taxacher
W. F. Weitze
R. A. Whipple
K. Wright
Subgroup on Elevated Temperature Design (BPV III)
R. I. Jetter, Chair
J. J. Abou-Hanna
T. Asayama
C. Becht
F. W. Brust
P. Carter
J. F. Cervenka
B. Dogan
D. S. Griffin
B. F. Hantz
A. B. Hull
M. H. Jawad
G. H. Koo
W. J. Kooves
D. L. Marriott
T. E. McGreevy
J. E. Nestell
W. J. O’Donnell
T.-L. Sham
R. W. Swindeman
D. P. Jones
G. Kharshafdjian
S. Majumdar
S. N. Malik
D. H. Roarty
G. Taxacher
A. Tsirigotis
K. Wright
H. H. Ziada
O. Jovall
N.-H. Lee
J. Munshi
N. Orbovic
B. B. Scott
R. E. Shewmaker
J. D. Stevenson
M. K. Thumm
M. L. Williams
T. D. Al-Shawaf, Contributing
Member
T. Muraki, Contributing
Member
M. R. Senecal, Contributing
Member
Working Group on Materials, Fabrication, and Examination
(BPV 3C)
J. F. Artuso, Chair
P. S. Ghosal, Vice Chair
M. L. Williams, Secretary
A. C. Eberhardt
J. Gutierrez
B. B. Scott
C. T. Smith
Working Group on Modernization (BPV 3C)
N. Alchaar, Chair
O. Jovall, Vice Chair
C. T. Smith, Secretary
J. F. Artuso
J. K. Harrold
COMMITTEE ON HEATING BOILERS (IV)
P. A. Molvie, Chair
T. L. Bedeaux, Vice Chair
G. Moino, Staff Secretary
J. Calland
J. P. Chicoine
C. M. Dove
B. G. French
W. L. Haag, Jr.
J. A. Hall
A. Heino
D. J. Jenkins
P. A. Larkin
K. M. McTague
B. W. Moore
T. M. Parks
J. L. Seigle
R. V. Wielgoszinski
H. Michael, Delegate
E. A. Nordstrom, Alternate
Subgroup on Care and Operation of Heating Boilers (BPV IV)
K. M. McTague
xxxv
P. A. Molvie
Subgroup on Cast Iron Boilers (BPV IV)
K. M. McTague, Chair
T. L. Bedeaux, Vice Chair
J. P. Chicoine
B. G. French
J. A. Hall
A. P. Jones
V. G. Kleftis
J. Kliess
P. A. Larkin
E. A. Nordstrom
Subgroup on Surface Examination Methods (BPV V)
A. S. Birks, Chair
S. J. Akrin
P. L. Brown
B. Caccamise
N. Y. Faransso
N. Farrenbaugh
N. A. Finney
Subgroup on Volumetric Methods (BPV V)
Subgroup on Materials (BPV IV)
P. A. Larkin, Chair
J. A. Hall, Vice Chair
A. Heino
B. J. Iske
J. Kliess
J. L. Seigle
Subgroup on Water Heaters (BPV IV)
W. L. Haag, Jr., Chair
J. Calland, Vice Chair
J. P. Chicoine
B. G. French
T. D. Gantt
B. J. Iske
A. P. Jones
K. M. McTague
O. A. Missoum
R. E. Olson
F. J. Schreiner
M. A. Taylor
T. E. Trant
G. W. Hembree, Chair
S. J. Akrin
J. E. Aycock
J. E. Batey
P. L. Brown
B. Caccamise
N. Y. Faransso
A. F. Garbolevsky
R. W. Hardy
R. A. Kellerhall
F. B. Kovacs
R. W. Kruzic
J. R. McGimpsey
M. D. Moles
A. B. Nagel
C. A. Nove
T. L. Plasek
F. J. Sattler
G. M. Gatti, Delegate
Working Group on Acoustic Emissions (SG-VM) (BPV V)
N. Y. Faransso, Chair
J. E. Aycock
J. E. Batey
R. K. Miller
Working Group on Radiography (SG-VM) (BPV V)
Subgroup on Welded Boilers (BPV IV)
T. L. Bedeaux, Chair
J. Calland, Vice Chair
C. M. Dove
B. G. French
A. P. Jones
G. W. Hembree
R. W. Kruzic
C. A. Nove
F. J. Sattler
F. C. Turnbull
G. M. Gatti, Delegate
E. A. Nordstrom
R. E. Olson
J. L. Seigle
R. V. Wielgoszinski
H. Michael, Delegate
F. B. Kovacs, Chair
S. J. Akrin
J. E. Aycock
J. E. Batey
P. L. Brown
B. Caccamise
N. Y. Faransso
A. F. Garbolevsky
R. W. Hardy
G. W. Hembree
R. W. Kruzic
J. R. McGimpsey
R. J. Mills
A. B. Nagel
C. A. Nove
T. L. Plasek
F. C. Turnbull
D. E. Williams
Working Group on Ultrasonics (SG-VM) (BPV V)
COMMITTEE ON
NONDESTRUCTIVE EXAMINATION (V)
J. E. Batey, Chair
F. B. Kovacs, Vice Chair
J. Brzuszkiewicz, Staff
Secretary
S. J. Akrin
C. A. Anderson
J. E. Aycock
A. S. Birks
P. L. Brown
N. Y. Faransso
A. F. Garbolevsky
G. W. Hembree
R. W. Kruzic
J. R. McGimpsey
M. D. Moles
A. B. Nagel
C. A. Nove
T. L. Plasek
F. J. Sattler
G. M. Gatti, Delegate
B. H. Clark, Jr., Honorary
Member
H. C. Graber, Honorary
Member
O. F. Hedden, Honorary
Member
J. R. MacKay, Honorary
Member
T. G. McCarty, Honorary
Member
Subgroup on General Requirements/
Personnel Qualifications and Inquiries (BPV V)
F. B. Kovacs, Chair
C. A. Anderson
J. E. Batey
A. S. Birks
N. Y. Faransso
G. W. Hembree
J. W. Houf
J. R. MacKay
J. P. Swezy, Jr.
R. W. Kruzic, Chair
J. E. Aycock
B. Caccamise
N. Y. Faransso
N. A. Finney
O. F. Hedden
R. A. Kellerhall
M. D. Moles
A. B. Nagel
C. A. Nove
F. J. Sattler
COMMITTEE ON PRESSURE VESSELS (VIII)
T. P. Pastor, Chair
U. R. Miller, Vice Chair
S. J. Rossi, Staff Secretary
T. Schellens, Staff Secretary
R. J. Basile
J. Cameron
D. B. DeMichael
J. P. Glaspie
M. Gold
J. F. Grubb
L. E. Hayden, Jr.
G. G. Karcher
K. T. Lau
J. S. Lee
R. Mahadeen
S. Malone
R. W. Mikitka
K. Mokhtarian
C. C. Neely
T. W. Norton
D. A. Osage
xxxvi
D. T. Peters
M. J. Pischke
M. D. Rana
G. B. Rawls, Jr.
S. C. Roberts
C. D. Rodery
A. Selz
J. R. Sims, Jr.
D. A. Swanson
K. K. Tam
S. Terada
E. Upitis
P. A. McGowan, Delegate
H. Michael, Delegate
K. Oyamada, Delegate
M. E. Papponetti, Delegate
D. Rui, Delegate
T. Tahara, Delegate
W. S. Jacobs, Contributing
Member
Subgroup on Design (BPV VIII)
U. R. Miller, Chair
R. J. Basile, Vice Chair
M. D. Lower, Secretary
O. A. Barsky
M. R. Breach
F. L. Brown
J. R. Farr
C. E. Hinnant
M. H. Jawad
R. W. Mikitka
K. Mokhtarian
D. A. Osage
T. P. Pastor
M. D. Rana
G. B. Rawls, Jr.
S. C. Roberts
C. D. Rodery
A. Selz
S. C. Shah
J. C. Sowinski
C. H. Sturgeon
D. A. Swanson
K. K. Tam
J. Vattappilly
R. A. Whipple
A. H. Gibbs, Delegate
K. Oyamada, Delegate
M. E. Papponetti, Delegate
W. S. Jacobs, Corresponding
Member
E. L. Thomas, Jr., Honorary
Member
Subgroup on High-Pressure Vessels (BPV VIII)
D. T. Peters, Chair
A. P. Maslowski, Staff
Secretary
L. P. Antalffy
R. C. Biel
P. N. Chaku
R. Cordes
R. D. Dixon
D. M. Fryer
R. T. Hallman
A. H. Honza
M. M. James
P. Jansson
J. A. Kapp
J. Keltjens
D. P. Kendall
A. K. Khare
Subgroup on Materials (BPV VIII)
Subgroup on Fabrication and Inspection (BPV VIII)
C. D. Rodery, Chair
J. P. Swezy, Jr., Vice Chair
B. R. Morelock, Secretary
J. L. Arnold
W. J. Bees
L. F. Campbell
H. E. Gordon
W. S. Jacobs
D. J. Kreft
J. S. Lee
D. A. Osage
M. J. Pischke
M. J. Rice
B. F. Shelley
P. L. Sturgill
T. Tahara
K. Oyamada, Delegate
R. Uebel, Delegate
S. C. Mordre
E. A. Rodriguez
E. D. Roll
J. R. Sims, Jr.
D. L. Stang
F. W. Tatar
S. Terada
R. Wink
K. Oyamada, Delegate
L. Fridlund, Corresponding
Member
M. D. Mann, Contributing
Member
G. J. Mraz, Contributing
Member
D. J. Burns, Honorary Member
E. H. Perez, Honorary
Member
J. F. Grubb, Chair
J. Cameron,Vice Chair
P. G. Wittenbach, Secretary
A. Di Rienzo
M. Gold
M. Katcher
W. M. Lundy
D. W. Rahoi
R. C. Sutherlin
E. Upitis
K. Oyamada, Delegate
E. E. Morgenegg,
Corresponding Member
E. G. Nisbett, Corresponding
Member
G. S. Dixit, Contributing
Member
J. A. McMaster, Contributing
Member
Subgroup on Toughness (BPV II & BPV VIII)
Subgroup on General Requirements (BPV VIII)
S. C. Roberts, Chair
D. B. DeMichael, Vice Chair
F. L. Richter, Secretary
R. J. Basile
D. T. Davis
J. P. Glaspie
L. E. Hayden, Jr.
K. T. Lau
M. D. Lower
C. C. Neely
A. S. Olivares
D. B. Stewart
D. A. Swanson
K. K. Tam
A. H. Gibbs, Delegate
K. Oyamada, Delegate
R. Uebel, Delegate
Subgroup on Heat Transfer Equipment (BPV VIII)
R. Mahadeen, Chair
T. W. Norton, Vice Chair
G. Aurioles
S. R. Babka
J. H. Barbee
O. A. Barsky
I. G. Campbell
A. Chaudouet
M. D. Clark
J. I. Gordon
M. J. Holtz
F. E. Jehrio
G. G. Karcher
D. L. Kurle
B. J. Lerch
S. Mayeux
U. R. Miller
R. J. Stastny
K. Oyamada, Delegate
F. Osweiller, Corresponding
Member
S. Yokell, Corresponding
Member
S. M. Caldwell, Honorary
Member
D. A. Swanson, Chair
J. L. Arnold
R. J. Basile
J. Cameron
H. E. Gordon
W. S. Jacobs
K. Mokhtarian
C. C. Neely
M. D. Rana
F. L. Richter
J. P. Swezy, Jr.
E. Upitis
J. Vattappilly
K. Oyamada, Delegate
Special Working Group on Graphite Pressure Equipment
(BPV VIII)
S. Malone, Chair
E. Soltow, Vice Chair
T. F. Bonn
F. L. Brown
R. W. Dickerson
B. Lukasch
M. R. Minick
A. A. Stupica
Task Group on Impulsively Loaded Vessels (BPV VIII)
R. E. Nickell, Chair
G. A. Antaki
J. K. Asahina
D. D. Barker
R. C. Biel
D. W. Bowman
A. M. Clayton
J. E. Didlake, Jr.
T. A. Duffey
B. L. Haroldsen
H. L. Heaton
xxxvii
D. Hilding
K. W. King
R. Kitamura
R. A. Leishear
P. Leslie
F. Ohlson
D. T. Peters
E. A. Rodriguez
C. Romero
J. E. Shepherd
COMMITTEE ON WELDING AND BRAZING (IX)
J. G. Feldstein, Chair
W. J. Sperko, Vice Chair
S. J. Rossi, Staff Secretary
D. A. Bowers
R. K. Brown, Jr.
M. L. Carpenter
P. D. Flenner
R. M. Jessee
J. S. Lee
W. M. Lundy
T. Melfi
W. F. Newell, Jr.
B. R. Newmark
A. S. Olivares
M. J. Pischke
M. J. Rice
M. B. Sims
M. J. Stanko
J. P. Swezy, Jr.
P. L. Van Fosson
R. R. Young
S. Raghunathan, Contributing
Member
S. D. Reynolds, Jr.,
Contributing Member
W. D. Doty, Honorary
Member
Subgroup on Brazing (BPV IX)
M. J. Pischke, Chair
E. W. Beckman
L. F. Campbell
M. L. Carpenter
A. F. Garbolevsky
J. P. Swezy, Jr.
Subgroup on General Requirements (BPV IX)
B. R. Newmark, Chair
E. W. Beckman
P. R. Evans
R. M. Jessee
A. S. Olivares
H. B. Porter
P. L. Sturgill
K. R. Willens
E. Molina, Delegate
Subgroup on Materials (BPV IX)
S. E. Gingrich
R. M. Jessee
C. C. Kim
T. Melfi
S. D. Reynolds, Jr.
C. E. Sainz
W. J. Sperko
M. J. Stanko
R. R. Young
V. Giunto, Delegate
Subgroup on Performance Qualification (BPV IX)
D. A. Bowers, Chair
V. A. Bell
L. P. Connor
R. B. Corbit
P. R. Evans
P. D. Flenner
K. L. Hayes
J. S. Lee
W. M. Lundy
E. G. Reichelt
M. B. Sims
G. W. Spohn III
Subgroup on Procedure Qualification (BPV IX)
D. A. Bowers, Chair
M. J. Rice, Secretary
M. Bernasek
R. K. Brown, Jr.
J. R. McGimpsey
W. F. Newell, Jr.
A. S. Olivares
S. D. Reynolds, Jr.
M. B. Sims
W. J. Sperko
S. A. Sprague
J. P. Swezy, Jr.
P. L. Van Fosson
T. C. Wiesner
E. Molina, Delegate
COMMITTEE ON
FIBER-REINFORCED PLASTIC PRESSURE VESSELS (X)
D. Eisberg, Chair
P. J. Conlisk, Vice Chair
P. D. Stumpf, Staff Secretary
F. L. Brown
J. L. Bustillos
T. W. Cowley
I. L. Dinovo
T. J. Fowler
M. R. Gorman
D. H. Hodgkinson
L. E. Hunt
D. L. Keeler
B. M. Linnemann
N. L. Newhouse
D. J. Painter
G. Ramirez
J. R. Richter
J. A. Rolston
B. F. Shelley
F. W. Van Name
D. O. Yancey, Jr.
P. H. Ziehl
COMMITTEE ON
NUCLEAR INSERVICE INSPECTION (XI)
G. C. Park, Chair
R. W. Swayne, Vice Chair
R. L. Crane, Staff Secretary
W. H. Bamford, Jr.
C. B. Cantrell
R. C. Cipolla
M. L. Coats
D. D. Davis
R. L. Dyle
E. L. Farrow
J. Fletcher
E. B. Gerlach
R. E. Gimple
F. E. Gregor
K. Hasegawa
D. O. Henry
J. C. Keenan
R. D. Kerr
S. D. Kulat
G. L. Lagleder
D. W. Lamond
G. A. Lofthus
W. E. Norris
K. Rhyne
D. A. Scarth
F. J. Schaaf, Jr.
J. C. Spanner, Jr.
G. L. Stevens
K. B. Thomas
E. W. Throckmorton III
D. E. Waskey
R. A. West
C. J. Wirtz
R. A. Yonekawa
K. K. Yoon
T. Yuhara
Y.-S. Chang, Delegate
J. T. Lindberg, Alternate
L. J. Chockie, Honorary
Member
C. D. Cowfer, Honorary
Member
O. F. Hedden, Honorary
Member
L. R. Katz, Honorary Member
P. C. Riccardella, Honorary
Member
Executive Committee (BPV XI)
R. W. Swayne, Chair
G. C. Park, Vice Chair
R. L. Crane, Staff Secretary
W. H. Bamford, Jr.
R. L. Dyle
R. E. Gimple
J. T. Lindberg
W. E. Norris
K. Rhyne
J. C. Spanner, Jr.
K. B. Thomas
R. A. West
R. A. Yonekawa
Subgroup on Evaluation Standards (SG-ES) (BPV XI)
W. H. Bamford, Jr., Chair
G. L. Stevens, Secretary
H.-D. Chung
R. C. Cipolla
G. H. DeBoo
R. L. Dyle
B. R. Ganta
T. J. Griesbach
K. Hasegawa
K. Hojo
D. N. Hopkins
Y. Imamura
xxxviii
K. Koyama
D. R. Lee
H. S. Mehta
J. G. Merkle
M. A. Mitchell
K. Miyazaki
S. Ranganath
D. A. Scarth
T.-L. Sham
K. R. Wichman
K. K. Yoon
Y.-S. Chang, Delegate
Working Group on Flaw Evaluation (SG-ES) (BPV XI)
R. C. Cipolla, Chair
G. H. DeBoo, Secretary
W. H. Bamford, Jr.
M. Basol
B. Bezensek
J. M. Bloom
H.-D. Chung
B. R. Ganta
R. G. Gilada
T. J. Griesbach
H. L. Gustin
F. D. Hayes
P. H. Hoang
K. Hojo
D. N. Hopkins
K. Koyama
D. R. Lee
H. S. Mehta
J. G. Merkle
K. Miyazaki
R. K. Qashu
S. Ranganath
D. L. Rudland
P. J. Rush
D. A. Scarth
W. L. Server
N. J. Shah
T. V. Vo
K. R. Wichman
G. M. Wilkowski
S. X. Xu
K. K. Yoon
V. A. Zilberstein
Working Group on Operating Plant Criteria (SG-ES) (BPV XI)
T. J. Griesbach, Chair
W. H. Bamford, Jr.
H. Behnke
B. A. Bishop
T. L. Dickson
R. L. Dyle
S. R. Gosselin
M. Hayashi
H. S. Mehta
M. A. Mitchell
R. Pace
S. Ranganath
W. L. Server
E. A. Siegel
D. V. Sommerville
G. L. Stevens
D. P. Weakland
K. K. Yoon
Working Group on Pipe Flaw Evaluation (SG-ES) (BPV XI)
D. A. Scarth, Chair
G. M. Wilkowski, Secretary
T. A. Bacon
W. H. Bamford, Jr.
B. Bezensek
H.-D. Chung
R. C. Cipolla
N. G. Cofie
J. M. Davis
G. H. DeBoo
B. Dogan
B. R. Ganta
L. F. Goyette
K. Hasegawa
P. H. Hoang
K. Hojo
D. N. Hopkins
K. Kashima
R. O. McGill
H. S. Mehta
K. Miyazaki
D. L. Rudland
P. J. Rush
T.-L. Sham
T. V. Vo
B. S. Wasiluk
S. X. Xu
K. K. Yoon
V. A. Zilberstein
Working Group on Personnel Qualification and Surface
Visual and Eddy Current Examination (SG-NDE) (BPV XI)
A. S. Reed, Chair
D. R. Cordes, Secretary
C. A. Anderson
B. L. Curtis
N. Farenbaugh
D. O. Henry
K. M. Hoffman
Working Group on Procedure Qualification
and Volumetric Examination (SG-NDE) (BPV XI)
M. E. Gothard, Chair
G. R. Perkins, Secretary
M. T. Anderson
C. B. Cheezem
A. D. Chockie
S. R. Doctor
F. E. Dohmen
K. J. Hacker
D. O. Henry
D. Kurek
G. L. Lagleder
J. T. Lindberg
G. R. Perkins
A. S. Reed
F. J. Schaaf, Jr.
C. J. Wirtz
R. A. Kellerhall
D. Kurek
G. A. Lofthus
C. E. Moyer
S. A. Sabo
R. V. Swain
S. J. Todd
Subgroup on Repair/Replacement Activities (SG-RRA) (BPV XI)
R. A. Yonekawa, Chair
E. V. Farrell, Jr., Secretary
S. B. Brown
R. E. Cantrell
P. D. Fisher
J. M. Gamber
E. B. Gerlach
R. E. Gimple
D. R. Graham
R. A. Hermann
K. J. Karwoski
J. C. Keenan
R. D. Kerr
S. L. McCracken
B. R. Newton
J. E. O’Sullivan
R. R. Stevenson
R. W. Swayne
D. E. Waskey
J. G. Weicks
E. G. Reichelt, Alternate
Working Group on Welding and Special Repair Processes
(SG-RRA) (BPV XI)
D. E. Waskey, Chair
D. J. Tilly, Secretary
R. E. Cantrell
S. J. Findlan
P. D. Fisher
M. L. Hall
R. A. Hermann
K. J. Karwoski
C. C. Kim
M. Lau
S. L. McCracken
D. B. Meredith
B. R. Newton
J. E. O’Sullivan
G. R. Poling
R. E. Smith
J. G. Weicks
K. R. Willens
Working Group on Design and Programs (SG-RRA) (BPV XI)
Subgroup on Nondestructive Examination (SG-NDE) (BPV XI)
J. C. Spanner, Jr., Chair
G. A. Lofthus, Secretary
C. A. Anderson
T. L. Chan
C. B. Cheezem
D. R. Cordes
F. E. Dohmen
M. E. Gothard
J. W. Houf
J. T. Lindberg
D. R. Quattlebaum, Jr.
D. Spake
J. C. Spanner, Jr.
M. C. Weatherly
C. J. Wirtz
E. B. Gerlach, Chair
S. B. Brown, Secretary
O. Bhatty
J. W. Collins
R. R. Croft
G. G. Elder
E. V. Farrell, Jr.
S. K. Fisher
J. M. Gamber
xxxix
D. R. Graham
G. F. Harttraft
T. E. Hiss
M. A. Pyne
R. R. Stevenson
R. W. Swayne
A. H. Taufique
T. P. Vassallo, Jr.
R. A. Yonekawa
Subgroup on Water-Cooled Systems (SG-WCS) (BPV XI)
K. B. Thomas, Chair
N. A. Palm, Secretary
J. M. Agold
V. L. Armentrout
J. M. Boughman
S. T. Chesworth
M. L. Coats
D. D. Davis
H. Q. Do
E. L. Farrow
M. J. Ferlisi
O. F. Hedden
Working Group on Pressure Testing (SG-WCS) (BPV XI)
D. W. Lamond, Chair
J. M. Boughman, Secretary
Y.-K. Chung
J. J. Churchwell
T. Coste
J. A. Doughty
G. L. Fechter IV
S. D. Kulat
D. W. Lamond
A. McNeill III
T. Nomura
W. E. Norris
G. C. Park
J. E. Staffiera
E. W. Throckmorton III
R. A. West
G. E. Whitman
H. L. Graves III, Alternate
Special Working Group on Editing and Review (BPV XI)
R. W. Swayne, Chair
C. E. Moyer
K. R. Rao
Working Group on Containment (SG-WCS) (BPV XI)
J. E. Staffiera, Chair
H. M. Stephens, Jr., Secretary
S. G. Brown
R. C. Cox
J. W. Crider
M. J. Ferlisi
P. S. Ghosal
D. H. Goche
J. E. Staffiera
D. J. Tilly
C. J. Wirtz
Special Working Group on Nuclear Plant Aging (BPV XI)
T. A. Meyer, Chair
D. V. Burgess, Secretary
S. Asada
Y.-K. Chung
D. D. Davis
F. E. Gregor
A. L. Hiser, Jr.
H. L. Graves III
H. T. Hill
R. D. Hough
C. N. Krishnaswamy
D. J. Naus
F. Poteet III
G. Thomas
W. E. Norris, Alternate
A. B. Meichler
R. E. Nickell
K. Sakamoto
W. L. Server
R. L. Turner
G. G. Young
G. E. Carpenter, Alternate
Special Working Group on High-Temperature Gas-Cooled
Reactors (BPV XI)
Working Group on ISI Optimization (SG-WCS) (BPV XI)
D. R. Cordes, Chair
S. A. Norman, Secretary
W. H. Bamford, Jr.
J. M. Boughman
J. W. Collins
M. E. Gothard
R. E. Hall
R. E. Hall
A. McNeill III
B. L. Montgomery
P. N. Passalugo
E. J. Sullivan, Jr.
E. W. Throckmorton III
J. Fletcher, Chair
M. A. Lockwood, Secretary
N. Broom
C. Cueto-Felgueroso
K. N. Fleming
S. R. Gosselin
M. R. Graybeal
A. H. Mahindrakar
S. A. Sabo
S. R. Scott
E. A. Siegel
K. B. Thomas
G. E. Whitman
Y. Yuguchi
A. B. Hull
R. K. Miller
M. N. Mitchell
T. Roney
F. J. Schaaf, Jr.
F. Shahrokhi
R. W. Swayne
Working Group on General Requirements (BPV XI)
K. Rhyne, Chair
E. J. Maloney, Secretary
G. P. Alexander
T. L. Chan
M. L. Coats
Working Group on Implementation of Risk-Based Examination
(SG-WCS) (BPV XI)
S. D. Kulat, Chair
S. T. Chesworth, Secretary
J. M. Agold
B. A. Bishop
C. Cueto-Felgueroso
H. Q. Do
R. Fougerousse
M. R. Graybeal
J. Hakii
K. W. Hall
K. M. Hoffman
A. T. Keim
D. W. Lamond
J. T. Lewis
R. K. Mattu
A. McNeill III
P. J. O’Regan
N. A. Palm
M. A. Pyne
J. C. Younger
COMMITTEE ON TRANSPORT TANKS (XII)
M. D. Rana, Chair
S. Staniszewski, Vice Chair
D. R. Sharp, Staff Secretary
A. N. Antoniou
C. H. Hochman
G. G. Karcher
N. J. Paulick
Working Group on Inspection of Systems and Components
(SG-WCS) (BPV XI)
J. M. Agold, Chair
V. L. Armentrout, Secretary
C. Cueto-Felgueroso
H. Q. Do
M. J. Ferlisi
R. Fougerousse
K. W. Hall
E. L. Farrow
J. C. Keenan
R. K. Mattu
S. R. Scott
G. E. Szabatura
M. D. Pham
M. Pitts
T. A. Rogers
A. Selz
W. K. Smith
A. P. Varghese
M. R. Ward
Subgroup on Design and Materials (BPV XII)
S. D. Kulat
T. A. Meyer
D. G. Naujock
T. Nomura
C. M. Ross
K. B. Thomas
G. E. Whitman
A. P. Varghese, Chair
R. C. Sallash, Secretary
P. Chilukuri
T. Hitchcock
G. G. Karcher
S. L. McWilliams
N. J. Paulick
xl
M. D. Pham
M. D. Rana
T. A. Rogers
A. Selz
M. R. Ward
E. A. Whittle
Subgroup on Fabrication and Inspection (BPV XII)
J. A. Byers
B. L. Gehl
L. D. Holsinger
COMMITTEE ON NUCLEAR CERTIFICATION (CNC)
R. R. Stevenson, Chair
W. C. LaRochelle, Vice Chair
J. Pang, Staff Secretary
M. N. Bressler
G. Deily
S. M. Goodwin
K. A. Huber
M. Kotb
J. C. Krane
R. P. McIntyre
M. R. Minick
H. B. Prasse
T. E. Quaka
D. M. Vickery
C. S. Withers
D. J. Kreft
A. S. Olivares
L. H. Strouse
Subgroup on General Requirements (BPV XII)
C. H. Hochman, Chair
A. N. Antoniou, Secretary
T. W. Alexander
J. L. Freiler
W. L. Garfield
K. L. Gilmore
M. Pitts
J. L. Rademacher
T. Rummel
R. C. Sallash
W. K. Smith
S. Staniszewski
L. H. Strouse
COMMITTEE ON
SAFETY VALVE REQUIREMENTS (BPV-SVR)
J. A. West, Chair
D. B. DeMichael, Vice Chair
C. E. O’Brien, Staff Secretary
J. F. Ball
S. Cammeresi
J. A. Cox
R. D. Danzy
R. J. Doelling
J. P. Glaspie
Subgroup on Nonmandatory Appendices (BPV XII)
T. A. Rogers, Chair
S. Staniszewski, Secretary
D. D. Brusewitz
J. L. Conley
T. Eubanks
B. L. Gehl
T. Hitchcock
M. F. Sullivan, Contributing
Member
P. D. Edwards, Alternate
D. P. Gobbi, Alternate
J. W. Highlands, Alternate
K. M. Hottle, Alternate
K. A. Kavanagh, Alternate
B. G. Kovarik, Alternate
B. L. Krasiun, Alternate
M. A. Lockwood, Alternate
R. J. Luymes, Alternate
L. M. Plante, Alternate
D. W. Stepp, Alternate
E. A. Whittle, Alternate
H. L. Wiger, Alternate
S. L. McWilliams
M. Pitts
J. L. Rademacher
A. Selz
D. G. Shelton
A. P. Varghese
M. R. Ward
S. F. Harrison, Jr.
W. F. Hart
D. Miller
T. M. Parks
D. K. Parrish
T. Patel
D. J. Scallan
Z. Wang
Subgroup on Design (BPV-SVR)
R. D. Danzy, Chair
C. E. Beair
J. A. Conley
R. J. Doelling
COMMITTEE ON BOILER AND
PRESSURE VESSEL CONFORMITY ASSESSMENT (CBPVCA)
D. Miller
T. Patel
T. R. Tarbay
J. A. West
Subgroup on General Requirements (BPV-SVR)
W. C. LaRochelle, Chair
P. D. Edwards, Vice Chair
K. I. Baron, Staff Secretary
W. J. Bees
S. W. Cameron
T. E. Hansen
D. J. Jenkins
K. T. Lau
L. E. McDonald
K. M. McTague
D. Miller
B. R. Morelock
J. D. O’Leary
T. M. Parks
B. C. Turczynski
D. E. Tuttle
E. A. Whittle
S. F. Harrison, Jr., Contributing
Member
D. B. DeMichael, Chair
J. F. Ball
G. Brazier
J. P. Glaspie
D. K. Parrish
D. C. Cook, Alternate
R. D. Danzy, Alternate
M. A. DeVries, Alternate
G. L. Hollinger, Alternate
D. W. King, Alternate
B. L. Krasiun, Alternate
P. F. Martin, Alternate
K. McPhie, Alternate
G. P. Milley, Alternate
M. R. Minick, Alternate
T. W. Norton, Alternate
F. J. Pavlovicz, Alternate
M. T. Roby, Alternate
J. A. West, Alternate
R. V. Wielgoszinski, Alternate
A. J. Spencer, Honorary
Member
J. W. Ramsey
J. W. Richardson
D. E. Tuttle
S. T. French, Alternate
Subgroup on Testing (BPV-SVR)
J. A. Cox, Chair
J. E. Britt
S. Cammeresi
G. D. Goodson
W. F. Hart
B. K. Nutter
D. J. Scallan
Z. Wang
U.S. Technical Advisory Group ISO/TC 185
Safety Relief Valves
T. J. Bevilacqua, Chair
C. E. O’Brien, Staff Secretary
J. F. Ball
G. Brazier
xli
D. B. DeMichael
D. Miller
B. K. Nutter
J. A. West
SUMMARY OF CHANGES
The 2010 Edition of this Code contains revisions in addition to the 2007 Edition with 2008 and 2009 Addenda.
The revisions are identified with the designation (10) in the margin and, as described in the Foreword, become
mandatory 6 months after the publication date of the 2010 Edition. To invoke these revisions before their
mandatory date, use the designation “2010 Edition” in documentation required by this Code. If you choose not
to invoke these revisions before their mandatory date, use the designation “2007 Edition through the 2009
Addenda” in documentation required by this Code.
The Record Numbers listed below are explained in more detail in “List of Changes in Record Number Order”
following this Summary of Changes.
Changes given below are identified on the pages by a margin note, (10), placed next to the affected area.
Page
Location
Change (Record Number)
xxv, xxvi
List of Sections
(1) Paragraph below “Addenda” editorially revised
(2) Second paragraph below “Interpretations” editorially
revised
(3) Paragraph below “Code Cases” editorially revised
xxvii, xxviii
Foreword
Ninth and eleventh paragraphs editorially revised
xxix
Statement of Policy
on the Use of
Code Symbols
(1) In the third paragraph, last sentence added
(2) Last paragraph deleted
6
Table U-3
(1) Publication year of standards CP-189 and SNT-TC-1A
each corrected to 2006 by errata (09-1335)
(2) Revised (07-1873)
11, 13, 14, 15
UG-11
Last sentence added to subpara. (c)(5) (03-373)
UG-16
Subparagraph (b)(5)(d) revised (09-375)
UG-19
(1) “Common Elements” title revised to read “Common
Element Design” and designated as (a)(1), and
subsequent subparagraphs redesignated accordingly
(08-1560)
(2) Paragraph references in subpara. (a)(2) revised
(08-1560)
(3) Subparagraph (a)(3) revised in its entirety (08-1560)
21
Figure UG-28.1
(1) Illustrations (b), (e), and (f) revised (03-122)
(2) Notes (1) and (3) revised (03-122)
30–33
UG-33
(1) In subpara. (b), “Ds” revised to “Dss”, “L” revised to
“Lc” and definition revised, and “Le” revised in its
entirety (03-1229)
(2) First paragraph in subpara. (f) revised in its entirety
(03-1229)
(3) Subparagraph (f)(1)(a), Step 9 revised in its entirety
(03-1229)
(4) Subparagraph (f)(1)(b), Step 5 revised in its entirety
(03-1229)
(5) Subparagraph (g) revised in its entirety (03-1229)
Figure UG-33.1
Caption revised (03-1229)
38–40
UG-36
Subparagraphs (b)(1), (c)(2)(a), and (c)(2)(c) revised
(08-973)
54
UG-45
Revised in its entirety (08-631)
xlii
Page
Location
Change (Record Number)
55
Table UG-45
Added (08-631)
62
UG-79
Subparagraph (a) revised in its entirety (03-373)
63, 64
UG-80
(1) Subparagraph (b)(10) deleted and subsequent
paragraph redesignated (08-837)
(2) Subparagraph (c) added (08-837)
74
UG-99
Subparagraph (b) revised in its entirety (08-697)
76, 78
UG-100
Subparagraph (b) revised in its entirety (08-697)
UG-101
Subparagraph (j)(1) revised to delete reference to
ASTM E 8 (07-1873)
UG-116
Subparagraph (j)(1) revised in its entirety (08-1560)
UG-117
(1) Subparagraph (a)(3)(a) revised (09-265)
(2) Seventh paragraph in subpara. (f) revised; footnote 41
revised (09-265)
86
Figure UG-118
Revised (08-23)
87
UG-120
Subparagraph (b) revised (08-1560)
93, 95
UG-129
(1) Subparagraphs (a)(3), (a)(5)(a), (a)(5)(c), and (a)(7)
revised (06-1436)
(2) Subparagraphs (a)(8) and (h) added (06-1436)
UG-131
Subparagraph (c)(3)(a) revised (07-488)
100
UG-133
(1) Subparagraph (g) revised (08-492)
(2) Subparagraph (h) added (07-488)
101–104
UG-136
(1) Subparagraph (a)(11) added (07-488)
(2) Subparagraph (c)(3) revised (07-1826)
(3) Subparagraph (c)(4)(b)(5) added, and subsequent
subparagraph redesignated (07-488)
(4) Subparagraph (c)(4)(c) deleted (06-123)
(5) Subparagraph (d)(2)(a) revised (06-123)
(6) Subparagraphs (d)(2)(d) and (d)(2)(e) deleted and
subsequent paragraphs redesignated (06-123)
105, 106
UG-137
(1) Subparagraph (c)(3) revised (07-1286)
(2) Subparagraph (d)(2)(e) revised (09-271)
82–85
111, 112
UW-2
Subparagraph (c) revised in its entirety (06-961)
126, 132, 133
UW-16
(1) In subpara. (a)(1), reference to UW-3(a)(4) corrected
by errata to read UW-(3)(d) (09-1782)
(2) Subparagraphs (c)(2)(a), (c)(2)(c), and (c)(2)(d) revised
to add “continuous” before “fillet weld” (09-47)
(3) Subparagraphs (f)(3)(a)(6) and (f)(4) revised (08-708)
(4) Subparagraphs (g)(2)(a) and (g)(2)(b)(2) revised
(08-1360)
Table UW-16.1
Added (08-708)
134
Figure UW-16.2
General Note revised (09-972)
136
Figure UW-16.3
Revised (08-1360)
140
UW-20.7
Added (07-1190)
UW-21
In subpara. (b), “fillet” deleted by errata (09-402,
09-1335)
Figure UW-21
(1) General Note corrected from “tn” to “tmin” by errata
(09-1782)
(2) Illustration (4) corrected to include tn by errata
(09-1335)
141
xliii
Page
Location
Change (Record Number)
146, 147
UW-40
(1) Last sentence added to subpara. (a) (09-1832)
(2) First sentence in subpara. (a)(8) revised (09-1832)
166
Table UCS-23
Grade P355GH added to Spec. No. SA/EN 10028-2
(09-203)
167, 168
UCS-56
In subpara. (d)(2), “120°C” corrected by errata to “140°C”
(09-1782)
175, 176
Table UCS-56
(1) P-No. 10A: In Note (4), “10°C” corrected by errata to
“28°C” (09-1782)
(2) P-No. 10C: In Note (4), “10°C” corrected by errata to
“28°C” (09-1782)
(3) P-No. 10F: In Note (2), “10°C” corrected by errata to
“28°C” (09-1782)
181
Figure UCS-66
In Notes (2)(a) and (4), Grades P355GH added (09-203)
199
Table UNF-23.4
UNS No. R56323 added to all Spec. Nos. (07-779)
202, 203
UNF-79
(1) Subparagraph (a)(2)(d) deleted; subpara. (a)(2)(c)
revised in its entirety (05-151)
(2) Subparagraph (b) revised (05-151)
Table UNF-79
General Note (b) revised (05-151)
Figure UNF-79
Deleted (05-151)
207
Table UHA-23
UNS No. S31277 deleted (09-1258)
212–215
UHA-44
(1) Subparagraph (a)(1)(d) deleted (05-151)
(2) Subparagraph (b) revised (05-151)
UHA-51
(1) Subparagraphs (a)(4)(b), (a)(4)(b)(2), and (a)(4)(b)(3)
revised (07-871)
(2) In subparas. (f)(4)(a) and (f)(4)(b), A9.12 revised to
A9.3.5, with additional information provided (07-871)
Table UHA-44
(1) General Note (b) revised (05-151)
(2) In Note (2), 120°C corrected to 140°C by errata
(09-1782)
Figure UHA-44
Deleted (05-151)
UHT-6
In subpara. (b), “Grade A” added following the SA-645
reference (09-281)
UHT-17
In subpara. (b), “Grade A” added following the SA-645
reference (09-281)
UHT-18
In subpara. (c), “Grade A” added following the SA-645
reference (09-281)
UHT-28
In subpara. (b), “Grade A” added following the SA-645
reference (09-281)
Table UHT-23
“Grade A” added to SA-645 (09-281)
238
UHT-56
In subpara. (e), “Grade A” added following the SA-645
reference (09-281)
239
Table UHT-56
“Grade A” added to SA-645 (09-281)
241
UHT-82
In subpara. (d), “Grade A” following the SA-645
reference (09-281)
269
Table ULT-23
“Grade A” added to SA-645 (09-281)
293, 295, 296
UHX-13.3
“Wt” added as nomenclature (05-484)
232–234
237
xliv
Page
Location
Change (Record Number)
UHX-13.4
(1) Subparagraphs (a) and (c) revised to include text
regarding tube-to-tubesheet joints (05-484)
(2) Subparagraph (e) deleted and subsequent
subparagraphs redesignated (05-484)
299, 303
UHX-13.5.9
Subparagraph (b) added, and subsequent subparagraphs
redesignated (05-484)
304
UHX-13.5.12
“Option 3” paragraph revised, and “Configuration a” and
“Configurations b and c” paragraphs deleted (06-17)
305
UHX-13.7.1
“Young’s modulus” changed to “modulus of elasticity” in
the third paragraph (05-484)
311, 312
UHX-14.3
“Wt” added as nomenclature (05-484)
UHX-14.4
(1) Subparagraphs (b) and (d) revised to include text
regarding tube-to-tubesheet joints (05-484)
(2) Subparagraph (f) deleted and subsequent
subparagraphs redesignated (05-484)
314, 315
UHX-14.5.9
Subparagraph (b) added, and subsequent subparagraphs
redesignated (05-484)
316
UHX-14.5.11
Revised (06-17)
317, 318
UHX-14.8
Added (05-484)
UHX-15
Deleted (05-484)
UHX-19.2.1
(1) In subpara. (a), reference to UG-19(a)(1) revised to
UG-19(a)(2) (08-1560)
(2) In subpara. (b), reference to UG-19(a)(2) revised to
UG-19(a)(3) (08-1560)
UHX-19.3
“And/or” deleted, and “or both” added (08-1560)
UHX-20.2.1
(1) Last sentence added to subpara. (a)(5) (07-1800)
(2) Nomenclature for Es,w added in subpara. (b)(3)
(07-1800)
(3) Nomenclature for “Flange Load” revised to “Bolt
Load” in subpara. (b)(4) (07-1800)
(4) Nomenclature for Za and Za added in subpara. (c)(4)
(07-1800)
(5) In subpara. (c)(10) in-text table added; subsequent intext table revised (07-1800)
(6) In subpara. (c)(11), in-text table added (07-1800)
(7) Subparagraph (c)(12) added, in-text table revised, and
subsequent subparagraphs redesignated (07-1800)
UHX-20.2.2
(1) Last sentence added to subpara. (a)(5) (07-1800)
(2) Nomenclature for Es,w added in subpara. (b)(3)
(07-1800)
(3) Nomenclature for “Flange Load” revised to “Bolt
Load” in subpara. (b)(4) (07-1800)
(4) Nomenclature for Za and Za added in subpara. (c)(4)
(07-1800)
(5) In subpara. (c)(10) in-text table added; subsequent intext table revised (07-1800)
(6) In subpara. (c)(11), in-text table added, in-text table
revised, and subsequent subparagraphs redesignated
(07-1800)
(7) Subparagraph (c)(12) added (07-1800)
319
325–334
xlv
Page
Location
Change (Record Number)
UHX-20.2.3
(1) Nomenclature for Es,w added in subpara. (b)(3)
(07-1800)
(2) Nomenclature for Za and Za added in subpara. (c)(3)
(07-1800)
(5) In subpara. (c)(9) in-text table added; subsequent intext table revised (07-1800)
(6) In subpara. (c)(10), title revised, in-text table added,
and subsequent subparagraphs redesignated
(07-1800)
Table UHX-20.2.1-1
“Allowable” revised to “Allowed” (07-1800)
Table UHX-20.2.2-1
“Allowable” revised to “Allowed” (07-1800)
Table UHX-20.2.3-2
“Allowable” revised to “Allowed” (07-1800)
Table UHX-20.2.3-3
“Allowable” revised to “Allowed” (07-1800)
341
Nonmandatory
Introduction
Subparagraphs (b), (c), and (e) revised (09-1241)
343
UIG-7
First sentence revised (09-1241)
344
UIG-29
Last sentence added (09-1241)
359
UIG-95
(1) Subparagraphs (a) and (c) revised (09-1241)
(2) Subparagraph (d) revised (09-1241)
UIG-97
Subparagraph (c) revised (09-1241)
360
UIG-121
Revised to include visual examination (09-1241)
374, 377
1-4
Subparagraph (f)(1)(d) revised to include “radians” in the
last equation (08-805)
382, 383
1-7
Subparagraphs (b), (b)(1)(c), and (c) revised (09-326)
388
1-10
Title revised and first paragraph added (08-973)
395
2-3
(1) Nomenclature for a added (06-1083)
(2) Nomenclature for Bs, Bsc, and Bsmax added (09-1174)
400, 401, 406, 407
2-5
(1) Subparagraph (d) revised (06-1083)
(2) In subpara. (e), equations renumbered to
accommodate the addition of eq. (3) in subpara. (d)
(06-1083)
2-6
Second and third paragraphs revised; last paragraph
added (06-1083)
2-7
Equations renumbered to accommodate the addition of
eq. (3) in subpara. (d) (06-1083)
454
12-2
Revised in its entirety (09-1461)
520
23-4
(1) Subparagraph (a)(1) deleted and subsequent
paragraphs redesignated (09-115)
(2) Subparagraph (b)(1) deleted and subsequent
paragraphs redesignated (09-115)
547
26-14.1.1
Spelling of “expansion” corrected by errata (09-1335)
548
26-14.1.2
(1) Figure references in subpara. (f) corrected by errata
(09-1335)
(2) Equation in subpara. (m)(3) corrected by errata
(09-1335)
549
26-14.2.2
Figure references in subpara. (h) corrected by errata
(09-1335)
xlvi
Page
Location
Change (Record Number)
567
32-4
Equation (3) in subpara. (a) revised (09-1809)
587, 588
A-1
Revised (01-576)
590, 592
A-2
Revised (01-576)
A-3
Subparagraphs (h), (i), and (k) revised (01-576)
A-4
Revised (01-576)
A-5
Revised (01-576)
665, 666
Form U-1
(1) Editorially revised
(2) Table under section 19 revised (08-998)
667
Form U-1A
(1) Editorially revised
(2) Table under section 10 revised (08-998)
669, 670
Form U-2
(1) Editorially revised
(2) Table under section 19 revised (08-998)
671
Form U-2A
(1) Editorially revised
(2) Table under section 11 revised (08-998)
672
Form U-3
(1) Editorially revised
(2) Table under section 12 revised (08-998)
674, 676, 677
Table W-3
(1) Note No. 13 editorially revised
(2) Note No. 43 revised (08-998)
(3) Note No. 53 revised (08-1560)
696
Nonmandatory
Appendix DD
Item 2 revised in its entirety (09-263)
726
Figure JJ-1.2-6
Revised (09-1058)
728
Form U-DR-1
Items 22 and 23 revised (08-843)
730
Form U-DR-2
Items 22 and 23 revised (08-843)
NOTE: Volume 60 of the Interpretations to Section VIII-1 of the ASME Boiler and Pressure Vessel Code
follows the last page of this Edition.
xlvii
LIST OF CHANGES IN RECORD NUMBER ORDER
Record Number
Change
01-576
Reconciled Nonmandatory Appendix A with Annex 4.C of Section VIII-2, revised definitions of k and tube
material tensile strength, added tensile strength ratio in the equation for L1 (test), and made editorial revisions.
Revised UG-11(d) to include a sentence that compels the vessel manufacturer to be responsible for ensuring
post forming heat treatment is conducted as required for parts that are supplied in a preformed condition by
another organization. Revised UG-79(a) by deleting the phrase “by any process that will not unduly impair
physical properties of the material.”
Revised Fig. UG-28.1 and UG-33 to make the rules in UG-33 in line with the rules in UG-28 by clarifying
that, when the cone-to-cylinder juncture is not a line-of-support, moment of inertia requirement in 1-8 need
not be met provided the nominal thickness of the cone section is not less than the minimum required thickness of the adjacent cylindrical shell. When a knuckle is not provided, the reinforcement required of 1-8
shall be satisfied. When the cone-to-cylinder juncture, with or without a knuckle, is a line-of-support, rules
in UG-33(f) shall be met (i.e., both moment of inertia and reinforcement requirements of 1-8 shall be met).
Revised UNF-79, Table UNF-79, UHA-44, and Table UHA-44 to make heat treatment mandatory for cold
formed swages, flares, and upsets in austenitic materials regardless of the extent of strain involved in the
forming. Deleted Figs. UNF-79 and UHA-44 regarding dimensions for strain calculations for cold formed
swages, flares, and upsets.
Added tube-to-tubesheet joint load requirements to UHX-13 and UHX-14, and deleted UHX-15.
Added elastic–plastic rules for floating tubesheet heat exchangers.
Deleted UG-136(c)(4)(c).
Reformatted and revised UW-2(c) to restore the original intent of the requirements, improve clarity, and
added limiting conditions under which ERW pipe may be used as the shell of an unfired steam boiler.
Added the maxinum bolt spacing equation and the bolt spacing correction factor to Mandatory Appendix 2.
Added UG-129(g) to allow for all metric units that are needed by pressure relief device manufacturers and
assemblers. Added example metric units to UG-129. Corrected UG-131(b)(2) to read 125°F (50°C).
Revised UG-129(a) to incorporate Code Case 1945-4, Restricting Lift to Achieve Reduced Relieving Capacities of Full Lift, Nozzle Type, Flat Seated Safety and Safety Relief Valves.
Added Grade 28 to Table UNF-23.4.
Revised UHA-51(a)(4) to correct invalid paragraph reference. Revised UHA-51(a)(4)(b) for clarity and consistency. Revised UHA-51(f)(4)(a) and (b) to mandate pre-use testing of welding consumables be conducted
utilizing the WPS to be used in production welding.
Added UW-20.7 to provide rules for clad tubesheets when the tubes are to be strength welded to the cladding.
Replaced the fixed tubesheet examples in UHX-20.2.
Revised pressure relief device certification interval for UG-136(c)(3) and UG-137(c)(3) from 5 yr to 6 yr.
Revised Table U-3 to update “year of acceptable edition” for those standards that were reviewed. Deleted
standards that are obsolete or not used from tables. Revised UG-101(j)(1) to delete the reference to
ASTM E 8 (as recommended by SGM). Made other editorial corrections as noted.
Revised Fig. UG-118 and its associated General Note.
Modified UG-133(g) to limit the use to compressible fluids.
Revised UG-45 to clarify minimum nozzle neck thickness. Added new Table UG-45.
Revised UG-99(b) and UG-100(b) to provide rules for the exclusion of bolting materials from the materials
used to determine the lowest ratio for the vessel.
Added Table UW-16.1. Changed the minimum fitting thickness in UW-16(f)(3)(a)(6) from ASME B16.11,
Class 3000, to that given in Table UW-16.1. Clarified UW-16(f)(4) so that the thickness for fittings smaller
than NPS 1⁄2 (DN 15) shall be Schedule 160 from Table 3 of ASME B16.11.
Added unit in radians to equations in Mandatory Appendix 1, 1-4(f)(1)(d).
Deleted UG-80(b)(10) and added UG-80(c).
Revised U-DR-1 and U-DR-2 by adding specific UG-22 loadings with a check box to indicate a requirement.
Revised UG-36 and 1-10 to specify that 1-10 rules can be used in lieu of UG-37 for all nozzle sizes.
Harmonized Forms U-1 (back), U-1A, U-2, U-2 (back), U-3 nozzle tables, and Table W-3, Note (43) to clarify data entry requirements.
Revised UW-16(g)(2)(a), UW-16(g)(2)(b)(2), and Fig. UW-16.3 to clarify the dimensions required.
03-373
03-1229
05-151
05-484
06-17
06-123
06-961
06-1083
06-1436
07-488
07-779
07-871
07-1190
07-1800
07-1826
07-1873
08-23
08-492
08-631
08-697
08-708
08-805
08-837
08-843
08-973
08-998
08-1360
xlviii
Record Number
Change
08-1560
Clarified the range of common element design temperatures permitted by UG-19(a)(3), added paragraph numbering to Common Element Design in UG-19(a)(1), renumbered the subsequent paragraphs, revised the
affected paragraph references, and eliminated “and/or” in the related paragraphs.
Revised UW-16(c)(2)(a), (b), (c), and (d) to clarify that the welds attaching a reinforcing element to the
shell must be continuous.
Removed the pressure limitations in Mandatory Appendix 23.
Updated Table UCS-23 and Notes to Fig. UCS-66 with Curve B in the as-rolled condition and Curve D in
the normalized condition.
Revised UG-117(a)(3)(a), UG-117(f), Nonmandatory Appendix DD, and Index.
Clarified in UG-136(d)(2)(a) the pressure containing parts subject to a hydrostatic test, including the addition
of a definition for the valve shell. Deleted existing UG-136(d)(2)(d) and (e). Renumbered existing paragraphs UG-136(d)(2)(f) and (g) as UG-136(d)(2)(d) and (e), respectively. Modified holder parts subject to
the hydrostatic test requirements in UG-137(d)(2)(e).
Added the Grade A designation for SA-645 in UHT-6(b), UHT-17(b), UHT-18(c), Table UHT-23,
UHT-28(b), UHT-56(e), Table UHT-56, UHT-82(d), and Table ULT-23.
Reformatted 1-7(b) and 1-7(b)(1). Removed reference to 1-7(c) in 1-7(b)(1)(c). Revised 1-7(c) for editorial
improvements and clarification of NDE requirements.
Revised UG-16(b)(5)(d) by deleting the 500 psi design requirement for tubing thickness.
Deleted the word “fillet” from UW-21(b).
Revised reference in Fig. UW-16.2 from “UW-16(f)(3)(a)” to “UW-16(f).”
Revised Fig. JJ-1.2-6’s UHA-51(d)(3) box to change “and” to “or.”
Revised the definition of the “bolt spacing” term (Bs) in Mandatory Appendix 2, 2-3 (Notation).
Removed obligatory Code words, “shall” and “must” in the nonmandatory Introduction, and replaced them
with “should.” Added the word “naturally” in reference to the porous nature of graphite in subpara. (b) for
clarity. Added specific ASTM references in UIG-7 so users could conduct appropriate testing. Added a rule
in UIG-29 to provide a usable value for yield strength, needed in UHX-14.5.9(b) calculations, because graphite does not yield when stressed like metals. In UIG-95(a), dealing with visual examination, replaced the
word “inspected“ by the more appropriate word “examined.” Deleted from subpara. (c) an inappropriate
word, “a,” and changed the work inspector to personnel. Added a subpara. (d) to provide and additional
needed examination. Made a very minor grammatical change noted in UIG-97(c). Added visual examination
records to the list of those that must be maintained in UIG-121.
Deleted SA-312 and SA-479, UNS S31277 references in Table UHA-23.
Corrected by errata.
Corrected by errata.
Deleted the NDE personnel qualification and certification requirements for UT examiners from 12-2, and
inserted a reference to those requirements in UW-54. Deleted Footnote 1 associated with the deleted text.
Revised eq. (3) in 32-4.
Revised UW-40.
Corrected by errata.
09-47
09-115
09-203
09-263
09-271
09-281
09-326
09-375
09-402
09-972
09-1058
09-1174
09-1241
09-1258
09-1335
09-1782
09-1461
09-1809
09-1832
10-114
xlix
INTENTIONALLY LEFT BLANK
l
2010 SECTION VIII — DIVISION 1
INTRODUCTION
construction under this Division. The Nonmandatory
Appendices provide information and suggested good practices.
SCOPE
U-1
SCOPE
U-1(a)
U-1(a)(1) The Foreword provides the basis for the
rules described in this Division.
U-1(a)(2) For the scope of this Division, pressure
vessels are containers for the containment of pressure,
either internal or external. This pressure may be obtained
from an external source, or by the application of heat from
a direct or indirect source, or any combination thereof.
U-1(a)(3) This Division contains mandatory requirements, specific prohibitions, and nonmandatory guidance
for pressure vessel materials, design, fabrication, examination, inspection, testing, certification, and pressure relief.
The Code does not address all aspects of these activities,
and those aspects which are not specifically addressed
should not be considered prohibited. Engineering judgment
must be consistent with the philosophy of this Division, and
such judgments must never be used to overrule mandatory
requirements or specific prohibitions of this Division. See
also informative and nonmandatory guidance regarding
metallurgical phenomena in Appendix A of Section II,
Part D.
U-1(b) This Division is divided into three Subsections,
Mandatory Appendices, and Nonmandatory Appendices.
Subsection A consists of Part UG, covering the general
requirements applicable to all pressure vessels. Subsection
B covers specific requirements that are applicable to the
various methods used in the fabrication of pressure vessels.
It consists of Parts UW, UF, and UB dealing with welded,
forged, and brazed methods, respectively. Subsection C
covers specific requirements applicable to the several
classes of materials used in pressure vessel construction.
It consists of Parts UCS, UNF, UHA, UCI, UCL, UCD,
UHT, ULW, ULT, and UIG dealing with carbon and low
alloy steels, nonferrous metals, high alloy steels, cast iron,
clad and lined material, cast ductile iron, ferritic steels with
properties enhanced by heat treatment, layered construction, low temperature materials, and impregnated graphite,
respectively. Section II, Part D also contains tables of
maximum allowable stress values for these classes of materials, except for impregnated graphite.
The Mandatory Appendices address specific subjects not
covered elsewhere in this Division, and their requirements
are mandatory when the subject covered is included in
U-1(c)
U-1(c)(1) The scope of this Division has been established to identify the components and parameters considered in formulating the rules given in this Division. Laws
or regulations issued by municipality, state, provincial,
federal, or other enforcement or regulatory bodies having
jurisdiction at the location of an installation establish the
mandatory applicability of the Code rules, in whole or in
part, within their jurisdiction. Those laws or regulations
may require the use of this Division of the Code for vessels
or components not considered to be within its Scope. These
laws or regulations should be reviewed to determine size
or service limitations of the coverage which may be different or more restrictive than those given here.
U-1(c)(2) Based on the Committee’s consideration,
the following classes of vessels are not included in the
scope of this Division; however, any pressure vessel which
meets all the applicable requirements of this Division may
be stamped with the Code U Symbol:
(a) those within the scope of other Sections;
(b) fired process tubular heaters;
(c) pressure containers which are integral parts or
components of rotating or reciprocating mechanical
devices, such as pumps, compressors, turbines, generators,
engines, and hydraulic or pneumatic cylinders where the
primary design considerations and /or stresses are derived
from the functional requirements of the device;
(d) except as covered in U-1(f), structures whose
primary function is the transport of fluids from one location
to another within a system of which it is an integral part,
that is,piping systems;
(e) piping components, such as pipe, flanges, bolting, gaskets, valves, expansion joints, fittings, and the pressure containing parts of other components, such as strainers
and devices which serve such purposes as mixing, separating, snubbing, distributing, and metering or controlling
flow, provided that pressure containing parts of such components are generally recognized as piping components or
accessories;
1
2010 SECTION VIII — DIVISION 1
(f) a vessel for containing water1 under pressure,
including those containing air the compression of which
serves only as a cushion, when none of the following
limitations are exceeded:
(1) a design pressure of 300 psi (2 MPa);
(2) a design temperature of 210°F (99°C);
(g) a hot water supply storage tank heated by steam
or any other indirect means when none of the following
limitations is exceeded:
(1) a heat input of 200,000 Btu /hr (58.6 kW);
(2) a water temperature of 210°F (99°C);
(3) a nominal water containing capacity of
120 gal (450 L);
(h) vessels not exceeding the design pressure (see
3-2), at the top of the vessel, limitations below, with no
limitation on size [see UG-28(f), 9-1(c)]:
(1) vessels having an internal or external pressure not exceeding 15 psi (100 kPa);
(2) combination units having an internal or
external pressure in each chamber not exceeding 15 psi
(100 kPa) and differential pressure on the common elements not exceeding 15 psi (100 kPa) [see UG-19(a)];
(i) vessels having an inside diameter, width, height,
or cross section diagonal not exceeding 6 in. (152 mm),
with no limitation on length of vessel or pressure;
(j) pressure vessels for human occupancy.2
U-1(d) The rules of this Division have been formulated
on the basis of design principles and construction practices
applicable to vessels designed for pressures not exceeding
3000 psi (20 MPa). For pressures above 3000 psi (20 MPa),
deviations from and additions to these rules usually are
necessary to meet the requirements of design principles
and construction practices for these higher pressures. Only
in the event that after having applied these additional design
principles and construction practices the vessel still complies with all of the requirements of this Division may it
be stamped with the applicable Code symbol.
U-1(e) In relation to the geometry of pressure containing parts, the scope of this Division shall include the
following:
U-1(e)(1) where external piping; other pressure vessels including heat exchangers; or mechanical devices, such
as pumps, mixers, or compressors, are to be connected to
the vessel:
(a) the welding end connection for the first circumferential joint for welded connections [see UW-13(h)];
(b) the first threaded joint for screwed connections;
(c) the face of the first flange for bolted, flanged
connections;
(d) the first sealing surface for proprietary connections or fittings;
U-1(e)(2) where nonpressure parts are welded
directly to either the internal or external pressure retaining
surface of a pressure vessel, this scope shall include the
design, fabrication, testing, and material requirements
established for nonpressure part attachments by the applicable paragraphs of this Division;3
U-1(e)(3) pressure retaining covers for vessel openings, such as manhole or handhole covers, and bolted covers with their attaching bolting and nuts;
U-1(e)(4) the first sealing surface for proprietary fittings or components for which rules are not provided by
this Division, such as gages, instruments, and nonmetallic
components.
U-1(f) The scope of the Division includes provisions
for pressure relief devices necessary to satisfy the requirements of UG-125 through UG-137 and Appendix 11.
U-1(g)(1) Unfired steam boilers shall be constructed in
accordance with the rules of Section I or this Division [see
UG-125(b) and UW-2(c)].
U-1(g)(2) The following pressure vessels in which
steam is generated shall not be considered as unfired steam
boilers, and shall be constructed in accordance with the
rules of this Division:
U-1(g)(2)(a) vessels known as evaporators or heat
exchangers;
U-1(g)(2)(b) vessels in which steam is generated
by the use of heat resulting from operation of a processing
system containing a number of pressure vessels such as
used in the manufacture of chemical and petroleum
products;
U-1(g)(2)(c) vessels in which steam is generated
but not withdrawn for external use.
U-1(h) Pressure vessels or parts subject to direct firing
from the combustion of fuel (solid, liquid, or gaseous),
which are not within the scope of Sections I, III, or IV
may be constructed in accordance with the rules of this
Division [see UW-2(d)].
U-1(i) Gas fired jacketed steam kettles with jacket
operating pressures not exceeding 50 psi (345 kPa) may
be constructed in accordance with the rules of this Division
(see Appendix 19).
U-1(j) Pressure vessels exclusive of those covered in
U-1(c), U-1(g), U-1(h), and U-1(i) that are not required
by the rules of this Division to be fully radiographed, which
are not provided with quick actuating closures (see UG-35),
and that do not exceed the following volume and pressure
1
The water may contain additives provided the flash point of the
aqueous solution at atmospheric pressure is 185°F or higher. The flash
point shall be determined by the methods specified in ASTM D 93 or in
ASTM D 56, whichever is appropriate.
2
Requirements for pressure vessels for human occupancy are covered
by ASME PVHO-1.
3
These requirements for design, fabrication, testing, and material for
nonpressure part attachments do not establish the length, size, or shape
of the attachment material. Pads and standoffs are permitted and the
scope can terminate at the next welded or mechanical joint.
2
2010 SECTION VIII — DIVISION 1
limits may be exempted from inspection by Inspectors, as
defined in UG-91, provided that they comply in all other
respects with the requirements of this Division:
U-1(j)(1) 5 cu ft (0.14 m3) in volume and 250 psi
(1.7 MPa) design pressure; or
U-1(j)(2) 3 cu ft (0.08 m3) in volume and 350 psi
(2.4 MPa) design pressure;
U-1(j)(3) 11⁄2 cu ft (0.04 m3) in volume and 600 psi
(4.1 MPa) design pressure.
In an assembly of vessels, the limitations in (1) through
(3) above apply to each vessel and not the assembly as a
whole. Straight line interpolation for intermediate volumes
and design pressures is permitted. Vessels fabricated in
accordance with this rule shall be marked with the “UM”
Symbol in Fig. UG-116 sketch (b) and with the data
required in UG-116. Certificates of Compliance shall satisfy the requirements of UG-120(a).
from the Manufacturer may be necessary for completion
of this form.
(b) Responsibilities5
(1) The Manufacturer of any vessel or part to be
marked with the Code Symbol has the responsibility of
complying with all of the applicable requirements of this
Division and, through proper certification, of assuring that
all work done by others also complies. The vessel or part
Manufacturer shall have available for the Inspector’s
review the applicable design calculations. See 10-5 and
10-15(d).
(2) Some types of work, such as forming, nondestructive examination, and heat treating, may be performed by
others (for welding, see UW-26 and UW-31). It is the
vessel or part Manufacturer’s responsibility to ensure that
all work so performed complies with all the applicable
requirements of this Division. After ensuring Code compliance, the vessel or part may be Code stamped by the
appropriate Code stamp holder after acceptance by the
Inspector.
(c) A vessel may be designed and constructed using any
combination of the methods of fabrication and the classes
of materials covered by this Division provided the rules
applying to each method and material are complied with
and the vessel is marked as required by UG-116.
(d) When the strength of any part cannot be computed
with a satisfactory assurance of safety, the rules provide
procedures for establishing its maximum allowable working pressure.
(e) It is the duty of the Inspector to make all of the
inspections specified by the rules of this Division, and of
monitoring the quality control and the examinations made
by the Manufacturer. He shall make such other inspections
as in his judgment are necessary to permit him to certify that
the vessel has been designed and constructed in accordance
with the requirements. The Inspector has the duty of verifying that the applicable calculations have been made and
are on file at Manufacturer’s plant at the time the Data
Report is signed. Any questions concerning the calculations
raised by the Inspector must be resolved. See UG-90(c)(1).
(f) The rules of this Division shall serve as the basis
for the Inspector to:
(1) perform the required duties;
(2) authorize the application of the Code Symbol;
(3) sign the Certificate of Shop (or Field Assembly)
Inspection.
(g) This Division of Section VIII does not contain rules
to cover all details of design and construction. Where complete details are not given, it is intended that the Manufacturer, subject to the acceptance of the Inspector, shall
GENERAL
U-2
GENERAL
(a) The user or his designated agent4 shall establish
the design requirements for pressure vessels, taking into
consideration factors associated with normal operation,
such other conditions as startup and shutdown, and abnormal conditions which may become a governing design
consideration (see UG-22).
Such consideration shall include but shall not be limited
to the following:
(1) the need for corrosion allowances;
(2) the definition of lethal services. For example, see
UW-2(a).
(3) the need for postweld heat treatment beyond the
requirements of this Division and dependent on service
conditions;
(4) for pressure vessels in which steam is generated,
or water is heated [see U-1(g) and (h)], the need for piping,
valves, instruments, and fittings to perform the functions
covered by PG-59 through PG-61 of Section I.
(5) the degree of nondestructive examinations(s) and
the selection of applicable acceptance standards, when such
examinations are applied, are beyond the requirements of
this Division.
Sample User Design Requirements forms and guidance
on their preparation are found in Nonmandatory
Appendix KK. This sample form might not be applicable
to all pressure vessels that may be constructed in accordance with this Division. The user is cautioned that input
4
For this Division, the user’s designated agent may be either a design
agency specifically engaged by the user, the Manufacturer of a system
for a specific service that includes a pressure vessel as a part and that is
purchased by the user, or an organization that offers pressure vessels for
sale or lease for specific services.
5
See UG-90(b) and UG-90(c)(1) for summaries of the responsibilities
of the Manufacturer and the duties of the Inspector.
3
2010 SECTION VIII — DIVISION 1
U-4
provide details of design and construction which will be
as safe as those provided by the rules of this Division.
(h) Field assembly of vessels constructed to this Division may be performed as follows.
(1) The Manufacturer of the vessel completes the
vessel in the field, completes the Form U-1 or U-1A Manufacturer’s Data Report, and stamps the vessel.
(2) The Manufacturer of parts of a vessel to be completed in the field by some other party stamps these parts
in accordance with Code rules and supplies the Form U2 or U-2A Manufacturer’s Partial Data Report to the other
party. The other party, who must hold a valid U Certificate
of Authorization, makes the final assembly, required NDE,
final pressure test; completes the Form U-1 or U-1A Manufacturer’s Data Report; and stamps the vessel.
(3) The field portion of the work is completed by a
holder of a valid U Certificate of Authorization other than
the vessel Manufacturer. The stamp holder performing the
field work is required to supply a Form U-2 or U-2A
Manufacturer’s Partial Data Report covering the portion
of the work completed by his organization (including data
on the pressure test if conducted by the stamp holder performing the field work) to the Manufacturer responsible
for the Code vessel. The vessel Manufacturer applies his
U Stamp in the presence of a representative from his Inspection Agency and completes the Form U-1 or U-1A Manufacturer’s Data Report with his Inspector.
In all three alternatives, the party completing and signing
the Form U-1 or U-1A Manufacturer’s Data Report
assumes full Code responsibility for the vessel. In all three
cases, each Manufacturer’s Quality Control System shall
describe the controls to assure compliance for each Code
stamp holder.
(i) For some design analyses, both a chart or curve and
a formula or tabular data are given. Use of the formula or
tabular data may result in answers which are slightly different from the values obtained from the chart or curve. However, the difference, if any, is within practical accuracy
and either method is acceptable.
U-3
UNITS OF MEASUREMENT6
Either U.S. Customary, SI, or any local customary units
may be used to demonstrate compliance with all requirements of this edition, e.g., materials, design, fabrication,examination, inspection, testing, certification, and
overpressure protection.
In general, it is expected that a single system of units
shall be used for all aspects of design except where unfeasible or impractical. When components are manufactured at
different locations where local customary units are different
than those used for the general design, the local units
may be used for the design and documentation of that
component. Similarly, for proprietary components or those
uniquely associated with a system of units different than
that used for the general design, the alternate units may be
used for the design and documentation of that component.
For any single equation, all variables shall be expressed
in a single system of units. When separate equations are
provided for U.S. Customary and SI units, those equations
must be executed using variables in the units associated
with the specific equation. Data expressed in other units
shall be converted to U.S. Customary or SI units for use
in these equations. The result obtained from execution of
these equations may be converted to other units.
Production, measurement and test equipment, drawings,
welding procedure specifications, welding procedure and
performance qualifications, and other fabrication documents may be in U.S. Customary, SI, or local customary
units in accordance with the fabricator’s practice. When
values shown in calculations and analysis, fabrication documents, or measurement and test equipment are in different
units, any conversions necessary for verification of Code
compliance and to ensure that dimensional consistency is
maintained, shall be in accordance with the following:
(a) Conversion factors shall be accurate to at least four
significant figures.
(b) The results of conversions of units shall be expressed
to a minimum of three significant figures.
Conversion of units, using the precision specified above
shall be performed to assure that dimensional consistency
is maintained. Conversion factors between U.S. Customary
and SI units may be found in the Nonmandatory Appendix,
Guidance for the Use of U.S. Customary and SI Units in
the ASME Boiler and Pressure Vessel Code. Whenever
local customary units are used the Manufacturer shall provide the source of the conversion factors which shall be
subject to verification and acceptance by the Authorized
Inspector or Certified Individual.
Material that has been manufactured and certified to
either the U.S. Customary or SI material specification (e.g.,
SA-516M) may be used regardless of the unit system used
STANDARDS REFERENCED BY THIS
DIVISION
(a) Throughout this Division references are made to
various standards, such as ANSI standards, which cover
pressure–temperature rating, dimensional, or procedural
standards for pressure vessel parts. These standards, with
the year of the acceptable edition, are listed in Table U-3.
(b) Rules for the use of these standards are stated elsewhere in this Division.
6
Guidance for conversion of units from U.S. Customary to SI is found
in Nonmandatory Appendix GG.
4
2010 SECTION VIII — DIVISION 1
in design. Standard fittings (e.g., flanges, elbows, etc.) that
have been certified to either U.S. Customary units or SI
units may be used regardless of the units system used in
design.
All entries on a Manufacturer’s Data Report and data
for Code-required nameplate marking shall be in units
consistent with the fabrication drawings for the component
using U.S. Customary, SI, or local customary units. It is
acceptable to show alternate units parenthetically. Users
of this Code are cautioned that the receiving jurisdiction
should be contacted to ensure the units are acceptable.
5
2010 SECTION VIII — DIVISION 1
(10)
TABLE U-3
YEAR OF ACCEPTABLE EDITION OF REFERENCED STANDARDS IN THIS DIVISION
Title
Number
Year
Seat Tightness of Pressure Relief Valves
API Std. 527
1991 (R2002)(1)
Unified Inch Screw Threads (UN and UNR Thread Form)
Pipe Threads, General Purpose (Inch)
ASME B1.1
ANSI/ASME
B1.20.1
2003
1983 (R2006)(1)
Cast Iron Pipe Flanges and Flanged Fittings, Classes 25,
125, and 250
Pipe Flanges and Flanged Fittings
Factory-Made Wrought Buttwelding Fittings
ASME B16.1
1998
ASME B16.5
ASME B16.9
2003(2)
2007
Forged Fittings, Socket-Welding and Threaded
Cast Bronze Threaded Fittings, Classes 125 and 250
Metallic Gaskets for Pipe Flanges — Ring-Joint, SpiralWound, and Jacketed
ASME B16.11
ASME B16.15
ASME B16.20
2005
1985 (R2004)(1)
2007
Cast Copper Alloy Pipe Flanges and Flanged Fittings, Class
150, 300, 400, 600, 900, 1500, and 2500
Ductile Iron Pipe Flanges and Flanged Fittings, Class 150
and 300
Large Diameter Steel Flanges, NPS 26 Through NPS 60
ASME B16.24
2001
ASME B16.42
1998
ASME B16.47
1996
Square and Hex Nuts (Inch Series)
Welded and Seamless Wrought Steel Pipe
Guidelines for Pressure Boundary Bolted Flange Joint
Assembly
Repair of Pressure Equipment and Piping
Pressure Relief Devices
Qualifications for Authorized Inspection
ASME B18.2.2
ASME B36.10M
ASME PCC-1
1987 (R1999)(1)
2004
2000
ASME PCC-2
ASME PTC 25
ASME QAI-1
2006
2001
2005 (3)
ASNT Central Certification Program
ACCP
ASNT Standard for Qualification and Certification of Nondestructive Testing Personnel
ANSI/ASNT
CP-189
Rev 3,
November 1997
2006
Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing
SNT-TC-1A
2006
Standard Test Methods for Flash Point by Tag Closed
Tester
Standard Test Methods for Flash Point by Pensky-Martens
Closed Tester
Pressure Relieving and Depressuring Systems
ASTM D 56
2002a
ASTM D 93
2002a
ANSI/API Std.
521
ASTM E 125
5th Ed., January
2007
1963 (R1985)(1)
ASTM E 140
ASTM E 186
2007
1998
ASTM E 208
2006
ASTM E 280
1998
ASTM E 446
1998
ANSI/UL-969
1991
Reference Photographs for Magnetic Particle Indications on
Ferrous Castings
Hardness Conversion Tables for Metals
Standard Reference Radiographs for Heavy-Walled [2 to
41⁄2-in. (51 to 114-mm)] Steel Castings
Method for Conducting Drop-Weight Test to Determine NilDuctility Transition Temperature of Ferritic Steels
Standard Reference Radiographs for Heavy-Walled (41⁄2 to
12-in. (114 to 305-mm)) Steel Castings
Standard Reference Radiographs for Steel Castings up to
2 in. (51 mm) in Thickness
Marking and Labeling Systems
6
2010 SECTION VIII — DIVISION 1
TABLE U-3
YEAR OF ACCEPTABLE EDITION OF REFERENCED STANDARDS
IN THIS DIVISION (CONT’D)
Title
Number
Charpy Pendulum Impact Test Part 1: Test Method
Charpy Pendulum Impact Test Part 2: Verification of Test
Machines
Charpy Pendulum Impact Test Part 3: Preparation and
Characterization of Charpy V Reference Test Pieces for
Verification of Test Machines
Year
ISO 148-1
ISO 148-2
2006
1998
ISO 148-3
1998
Metric Standards
Metric Screw Thread — M Profile
Metric Screw Thread — MJ Profile
Metric Heavy Hex Screws
Metric Hex Bolts
ASME
ASME
ASME
ASME
B1.13M
B1.21M
B18.2.3.3M
B18.2.3.5M
2001
1997
1979 (R2001)
1979 (R2001)
Metric
Metric
Metric
Metric
ASME
ASME
ASME
ASME
B18.2.3.6M
B18.2.4.1M
B18.2.4.2M
B18.2.4.6M
1979 (R2001)
2002
1979 (R1995)
1979 (R2003)
Heavy Hex Bolts
Hex Nuts, Style 1
Hex Nuts, Style 2
Heavy Hex Nuts
NOTES:
(1) R — Reaffirmed.
(2) See UG-11(a)(2).
(3) See UG-91 and UG-117(f).
7
2010 SECTION VIII — DIVISION 1
SUBSECTION A
GENERAL REQUIREMENTS
PART UG
GENERAL REQUIREMENTS FOR ALL METHODS
OF CONSTRUCTION AND ALL MATERIALS
UG-1
SCOPE
(c) Material covered by specifications in Section II is
not restricted as to the method of production unless so
stated in the specification, and so long as the product complies with the requirements of the specification. (See
UG-85.)
(d) Materials other than those allowed by this Division
may not be used, unless data thereon are submitted to and
approved by the Boiler and Pressure Vessel Committee in
accordance with Appendix 5 in Section II, Part D.
(e) Materials outside the limits of size and /or thickness
given in the title or scope clause of the specifications given
in Section II, and permitted by the applicable part of Subsection C, may be used if the material is in compliance
with the other requirements of the specification,1 and no
size or thickness limitation is given in the stress tables.
In those specifications in which chemical composition or
mechanical properties vary with size or thickness, materials
outside the range shall be required to conform to the composition and mechanical properties shown for the nearest
specified range.
(f) It is recommended that the user or his designated
agent assure himself that materials used for the construction
of the vessels will be suitable for the intended service with
respect to retention of satisfactory mechanical properties,
and resistance to corrosion, erosion, oxidation, and other
deterioration during their intended service life. See also
The requirements of Part UG are applicable to all pressure vessels and vessel parts and shall be used in conjunction with the specific requirements in Subsections B and
C and the Mandatory Appendices that pertain to the method
of fabrication and the material used.
MATERIALS
UG-4
GENERAL
(a) Material subject to stress due to pressure shall conform to one of the specifications given in Section II, Part
D, Subpart 1, Tables 1A, 1B, and 3, including all applicable
notes in the tables, and shall be limited to those that are
permitted in the applicable Part of Subsection C, except
as otherwise permitted in UG-9, UG-10, UG-11, UG-15,
Part UCS, Part UIG, and the Mandatory Appendices. Material may be identified as meeting more than one material
specification and /or grade provided the material meets all
requirements of the identified material specification(s)
and /or grade(s) [see UG-23(a)].
(b) Material for nonpressure parts, such as skirts, supports, baffles, lugs, clips, and extended heat transfer surfaces, need not conform to the specifications for the
material to which they are attached or to a material specification permitted in this Division, but if attached to the
vessel by welding shall be of weldable quality [see
UW-5(b)]. The allowable stress values for material not
identified in accordance with UG-93 shall not exceed 80%
of the maximum allowable stress value permitted for similar material in Subsection C.
1
In some instances the limitations of the scope clause in the material
specifications are based on a very realistic maximum. It is recommended
that the designer and /or fabricator confer with the material manufacturer
or supplier before proceeding, thus assuring himself that except for size
or thickness, all requirements of the material specification will be met
and so certified.
8
2010 SECTION VIII — DIVISION 1
informative and nonmandatory guidance regarding metallurgical phenomena in Appendix A of Section II, Part D.
(g) When specifications, grades, classes, and types are
referenced, and the material specification in Section II, Part
A or Part B is a dual-unit specification (e.g., SA-516/SA516M), the design values and rules shall be applicable to
either the U.S. Customary version of the material specification or the SI unit version of the material specification.
For example, when SA-516M Grade 485 is used in construction, the design values listed for its equivalent, SA-516
Grade 70, in either the U.S. Customary or metric Section
II, Part D (as appropriate) shall be used.
UG-5
tubes are given in the tables referenced in UG-23.
(b) Integrally finned tubes may be made from tubes that
conform in every respect with one of the specifications
given in Section II. These tubes may be used under the
following conditions:
(1) The tubes, after finning, shall have a temper or
condition that conforms to one of those provided in the
governing specifications, or, when specified, they may be
furnished in the “as-fabricated condition” where the finned
portions of the tube are in the cold worked temper (asfinned) resulting from the finning operation, and the
unfinned portions in the temper of the tube prior to finning.
(2) The maximum allowable stress value for the
finned tube shall be that given in the tables referenced in
UG-23 for the tube before finning except as permitted in
(3) below.
(3) The maximum allowable stress value for a temper
or condition that has a higher stress value than that of the
tube before finning may be used provided that qualifying
mechanical property tests demonstrate that such a temper
or condition is obtained and conforms to one of those
provided in the governing specifications in Section II, and
provided that allowable stress values have been established
in the tables referenced in UG-23 for the tube material
used. The qualifying mechanical property tests shall be
made on specimens of finned tube from which the fins
have been removed by machining. The frequency of tests
shall be as required in the unfinned tube specification.
(4) The maximum allowable internal or external
working pressure of the tube shall be based on the root
diameter and the minimum wall of the finned section, or
the outside diameter and wall of the unfinned section
together with appropriate stress values, whichever results
in the lower maximum allowable working pressure. Alternatively, the maximum allowable external pressure for
tubes with integral fins may be established under the rules
of Appendix 23.
(5) In addition to the tests required by the governing
specifications, each tube after finning shall be subjected to
a pneumatic test or a hydrostatic test as indicated below.
UG-90(c)(1)(i) requirement for a visual inspection by the
Inspector does not apply to either of these tests.
(a) an internal pneumatic test of not less than 250
psi (1.7 MPa) for 5 sec without evidence of leakage. The
test method shall permit easy visual detection of any leakage such as immersion of the tube under water or a pressure
differential method.4
(b) an individual tube hydrostatic test in accordance with UG-99 that permits complete examination of
the tube for leakage.
PLATE2
Plate used in the construction of pressure parts of pressure vessels shall conform to one of the specifications in
Section II for which allowable stress values are given in the
tables referenced in UG-23, except as otherwise provided in
UG-4, UG-10, UG-11, and UG-15.
UG-6
FORGINGS
(a) Forged material may be used in pressure vessel construction provided the material has been worked sufficiently to remove the coarse ingot structure. Specifications
and maximum allowable stress values for acceptable forging materials are given in the tables referenced in UG-23.
(See Part UF for forged vessels.)
(b) Forged rod or bar may only be used within the
limitations of UG-14.
UG-7
CASTINGS
Cast material may be used in the construction of pressure
vessels and vessel parts. Specifications and maximum
allowable stress values for acceptable casting materials are
given in the tables referenced in UG-23. These allowable
stress values shall be multiplied by the applicable casting
quality factor given in UG-24 for all materials except
cast iron.
UG-8
PIPE AND TUBES
(a) Pipe and tubes of seamless or welded3 construction
conforming to one of the specifications given in Section
II may be used for shells and other parts of pressure vessels.
Allowable stress values for the materials used in pipe and
2
The term “plate” for the purpose of this usage includes sheet and
strip also.
3
Pipe and tubing fabricated by fusion welding, with filler metal added,
may not be used in Code construction unless it is fabricated in accordance
with Code rules as a pressure part.
4
The pressure differential method is described in “Materials Research
Standards,” Vol. 1, No. 7, July 1961, published by ASTM.
9
2010 SECTION VIII — DIVISION 1
UG-9
WELDING MATERIALS
designation of the specification to which the material is
recertified and with the notation “Certified per UG-10.”
(2) Recertification by the Vessel or Part Manufacturer
(a) A copy of the certification by the material manufacturer of the chemical analysis required by the permitted
specification, with documentation showing the requirements to which the material was produced and purchased,
and which demonstrates that there is no conflict with the
requirements of the permitted specification, is available to
the Inspector.
(b) For applications in which the maximum allowable stresses are subject to a cautionary note, documentation is available to the Inspector that establishes what
deoxidation was performed during the material manufacture, to the degree necessary for the vessel or part Manufacturer to make a decision with regard to the cautionary note.
(c) Documentation is available to the Inspector that
demonstrates that the metallurgical structure, mechanical
property, and hardness requirements of the permitted specification have been met.
(d) For material recertified to a permitted specification that requires a fine austenitic grain size or that
requires that a fine grain practice be used during melting,
documentation is available to the Inspector that demonstrates that the heat treatment requirements of the permitted
specification have been met, or will be met during fabrication.
(e) The material has marking, acceptable to the
Inspector, for identification to the documentation.
(f) When the conformance of the material with the
permitted specification has been established, the material
has been marked as required by the permitted specification.
(b) Material Identified to a Particular Production Lot
as Required by a Specification Permitted by This Division
but Which Cannot Be Qualified Under UG-10(a). Any
material identified to a particular production lot as required
by a specification permitted by this Division, but for which
the documentation required in UG-10(a) is not available,
may be accepted as satisfying the requirements of the specification permitted by this Division provided that the conditions set forth below are satisfied.
(1) Recertification by an Organization Other Than
the Vessel or Part Manufacturer. Not permitted.
(2) Recertification by the Vessel or Part Manufacturer
(a) Chemical analyses are made on different pieces
from the lot to establish a mean analysis that is to be
accepted as representative of the lot. The pieces chosen
for analysis shall be selected at random from the lot. The
number of pieces selected shall be at least 10% of the
number of pieces in the lot, but not less than three. For
lots of three pieces or less, each piece shall be analyzed.
Each individual analysis for an element shall conform to
Welding materials used for production shall comply with
the requirements of this Division, those of Section IX, and
the applicable qualified welding procedure specification.
When the welding materials comply with one of the specifications in Section II, Part C, the marking or tagging of
the material, containers, or packages as required by the
applicable Section II specification may be accepted for
identification in lieu of a Certified Test Report or a Certificate of Compliance. When the welding materials do not
comply with one of the specifications of Section II, the
marking or tagging shall be identifiable with the welding
materials set forth in the welding procedure specification,
and may be accepted in lieu of a Certified Test Report or
a Certificate of Compliance.
UG-10
MATERIAL IDENTIFIED WITH OR
PRODUCED TO A SPECIFICATION
NOT PERMITTED BY THIS
DIVISION, AND MATERIAL NOT
FULLY IDENTIFIED
(a) Identified Material With Complete Certification
From the Material Manufacturer. Material identified with
a specification not permitted by this Division, or procured
to chemical composition requirements, and identified to a
single production lot as required by a permitted specification may be accepted as satisfying the requirements of
a specification permitted by this Division provided the
conditions set forth in (1) or (2) below are satisfied.
(1) Recertification by an Organization Other Than
the Vessel or Part Manufacturer
(a) All requirements, including but not limited to,
melting method, melting practice, deoxidation, quality, and
heat treatment, of the specification permitted by this Division, to which the material is to be recertified, have been
demonstrated to have been met.
(b) A copy of the certification by the material manufacturer of the chemical analysis required by the permitted
specification, with documentation showing the requirements to which the material was produced and purchased,
and which demonstrates that there is no conflict with the
requirements of the permitted specification, has been furnished to the vessel or part Manufacturer.
(c) A certification that the material was manufactured and tested in accordance with the requirements of
the specification to which the material is recertified, excluding the specific marking requirements, has been furnished
to the vessel or part Manufacturer, together with copies of
all documents and test reports pertinent to the demonstration of conformance to the requirements of the permitted
specification.
(d) The material and the Certificate of Compliance
or the Material Test Report have been identified with the
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2010 SECTION VIII — DIVISION 1
of only one of the two specimens need conform to the
maximum requirement.
(b) The provisions of (b)(2)(c), (b)(2)(d), and
(b)(2)(e) above are met.
(c) When the identity of the material with the permitted specification has been established in accordance
with (a) and (b) above, each piece (or bundle, etc., if
permitted in the specification) is marked with a marking
giving the permitted specification number and grade, type,
or class as applicable and a serial number identifying the
particular lot of material. A suitable report, clearly marked
as being a “Report on Tests of Nonidentified Material,”
shall be completed and certified by the vessel or part Manufacturer. This report, when accepted by the Inspector, shall
constitute authority to use the material in lieu of material
procured to the requirements of the permitted specification.
the limits for product analysis in the permitted specification, and the mean for each element shall conform to the
heat analysis limits of that specification. Analyses need
only be made for those elements required by the permitted
specification. However, consideration should be given to
making analyses for elements not specified in the specification but that would be deleterious if present in excessive
amounts.
(b) Mechanical property tests are made in accordance with the requirements of the permitted specification,
and the results of the tests conform to the specified requirements.
(c) For applications in which the maximum allowable stresses are subject to a cautionary note, chemical
analysis results are obtained that are sufficient to establish
what deoxidation was used during the material manufacture, to the degree necessary for making a decision with
regard to the cautionary note.
(d) When the requirements of the permitted specification include metallurgical structure requirements (i.e.,
fine austenitic grain size), tests are made and the results
are sufficient to establish that those requirements of the
specification have been met.
(e) When the requirements of the permitted specification include heat treatment, the material is heat treated
in accordance with those requirements, either prior to or
during fabrication.
(f) When the conformance of the material with the
permitted specification has been established, the material
has been marked as required by the permitted specification.
(c) Material Not Fully Identified. Material that cannot
be qualified under the provisions of either UG-10(a) or
UG-10(b), such as material not fully identified as required
by the permitted specification or unidentified material, may
be accepted as satisfying the requirements of a specification
permitted by this Division provided that the conditions set
forth below are satisfied.
(1) Qualification by an Organization Other Than the
Vessel or Part Manufacturer. Not permitted.
(2) Qualification by the Vessel or Part Manufacturer
(a) Each piece is tested to show that it meets the
chemical composition for product analysis and the mechanical properties requirements of the permitted specification.
Chemical analyses need only be made for those elements
required by the permitted specification. However, consideration should be given to making analyses for elements not
specified in the specification but that would be deleterious
if present in excessive amounts. For plates, when the direction of final rolling is not known, both a transverse and a
longitudinal tension test specimen shall be taken from each
sampling location designated in the permitted specification.
The results of both tests shall conform to the minimum
requirements of the specification, but the tensile strength
UG-11
PREFABRICATED OR PREFORMED
PRESSURE PARTS
Prefabricated or preformed pressure parts for pressure
vessels that are subject to allowable working stresses due
to internal or external pressure in the vessel and that are
furnished by other than the location of the Manufacturer
responsible for the vessel to be marked with the Code
Symbol shall conform to all applicable requirements of
this Division as related to the vessel, including service
restrictions applicable to the material, inspection in the
shop of the parts Manufacturer, and the furnishing of Partial
Data Reports as provided for in UG-120(c) except as permitted in (a), (b), and (c) below. Manufacturers with multiple locations, each with its own Certificate of
Authorization, may transfer pressure vessel parts from one
of its locations to another without Partial Data Reports,
provided the Quality Control System describes the method
of identification, transfer, and receipt of the parts. When
the prefabricated or preformed parts are furnished with a
nameplate and the nameplate interferes with further fabrication or service, and where stamping on the material is
prohibited, the Manufacturer of the completed vessel, with
the concurrence of the Authorized Inspector, may remove
the nameplate. The removal of the nameplate shall be noted
in the “Remarks” section of the vessel Manufacturer’s Data
Report. The nameplate shall be destroyed. The rules of (a),
(b), and (c) below shall not be applied to quick-actuating
closures [UG-35(b)].
(a) Cast, Forged, Rolled, or Die Formed Standard Pressure Parts
(1) Pressure parts, such as pipe fittings, flanges, nozzles, welding necks, welding caps, manhole frames and
covers, that are wholly formed by casting, forging, rolling,
or die forming shall not require inspection, identification
in accordance with UG-93(a) or (b), or Partial Data Reports.
Standard pressure parts that comply with some ASME
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2010 SECTION VIII — DIVISION 1
standard5 shall be made of materials permitted by this
Division or of materials specifically listed in an ASME
product standard listed elsewhere in this Division. Standard
pressure parts that comply with a Manufacturer’s standard6,7 shall be made of materials permitted by this Division. Parts made to either an ASME standard or
Manufacturer’s standard shall be marked with the name
or trademark of the parts manufacturer and such other
markings as are required by the standard. Such markings
shall be considered as the parts Manufacturer’s certification
that the product complies with the material specifications
and standards indicated and is suitable for service at the
rating indicated. The intent of this paragraph will have
been met if, in lieu of the detailed marking on the part
itself, the parts described herein have been marked in any
permanent or temporary manner that will serve to identify
the part with the parts manufacturer’s written listing of the
particular items and such listings are available for examination by the Inspector.
(2) Flanges and flanged fittings may be used at the
pressure–temperature ratings specified in the appropriate
standard listed in this Division. Other pressure–temperature
ratings may be used if the flange satisfies the requirements
of UG-11(a)(1) and, using the specified gaskets and bolting,
satisfies the design requirements of UG-34 or Appendix 2
of this Division.
(3) Parts of small size falling within this category
for which it is difficult or impossible to obtain identified
material or which may be stocked and for which identification in accordance with UG-93 cannot be economically
obtained and are not customarily furnished, and that do
not appreciably affect the safety of the vessel, may be used
for relatively unimportant parts or parts stressed to not
more than 50% of the stress value permitted by this Division provided they are suitable for the purpose intended
and are acceptable to the Inspector [see (a)(1) above and
UG-4(b)]. The Manufacturer of the vessel to be marked
with the Code Symbol shall satisfy himself that the part
is suitable for the design conditions specified for the vessel
in accordance with the rules of this Division.
(b) Cast, Forged, Rolled, or Die Formed Nonstandard
Pressure Parts. Pressure parts such as shells, heads, removable doors, and pipe coils that are wholly formed by casting,
forging, rolling, or die forming may be supplied basically
as materials. All such parts shall be made of materials
permitted under this Division and the Manufacturer of the
part shall furnish identification in accordance with UG-93.
Such parts shall be marked with the name or trademark of
the parts Manufacturer and with such other markings as will
serve to identify the particular parts with accompanying
material identification. The Manufacturer of the vessel to
be marked with the Code Symbol shall satisfy himself that
the part is suitable for the design conditions specified for
the completed vessel in accordance with the rules of this
Division.
(c) Welded Standard Pressure Parts for Use Other Than
the Shell or Heads of a Vessel. Pressure parts, such as
welded standard pipe fittings, welding caps, and flanges
that are fabricated by one of the welding processes recognized by this Division shall not require inspection, identification in accordance with UG-93(a) or (b), or Partial Data
Reports provided:
(1) standard pressure parts that comply with some
ASME product standard5shall be made of materials permitted by this Division or of materials specifically listed in an
ASME product standard listed elsewhere in this Division.
Standard pressure parts that comply with a Manufacturer’s
standard6,7shall be made of materials permitted by this
Division.
(2) welding for pressure parts that comply with a
Manufacturer’s standard6,7shall comply with the requirements of UW-26(a), (b), and (c) and UW-27 through
UW-40. Welding for pressure parts that comply with some
ASME product standard5shall comply with the requirements of UW-26(a), (b), and (c) and UW-27 through
UW-40, or with the welding requirements of SA-234.
Markings, where applicable, or Certification by the parts
Manufacturer where markings are not applicable, shall be
accepted as evidence of compliance with the above welding
requirements. Such parts shall be marked as required by
UG-11(a)(1).
Such parts shall be marked with the name or trademark
of the parts manufacturer and with such other markings as
will serve to identify the materials of which the parts are
made. Such markings shall be considered as the parts Manufacturer’s certification that the product complies with (1)
above. A statement by the parts Manufacturer that all welding complies with Code requirements shall be accepted as
evidence that the product complies with (2) above.
(3) if radiography or postweld heat treatment is
required by the rules of this Division, it may be performed
either in the plant of the parts Manufacturer or in the plant
of the Manufacturer of the vessel to be marked with the
Code Symbol.
If the radiographing is done under the control of the
parts Manufacturer, the completed radiographs, properly
identified, with a radiographic inspection report, shall be
5
These are pressure parts which comply with some ASME product
standard accepted by reference in UG-44. The ASME product standard
establishes the basis for the pressure–temperature rating and marking
unless modified in UG-44.
6
These are pressure parts that comply with a parts Manufacturer’s
standard that defines the pressure–temperature rating marked on the part
and described in the parts Manufacturer’s literature. The Manufacturer
of the completed vessel shall satisfy him/herself that all such parts used
comply with the applicable rules of this Division and are suitable for the
design conditions of the completed vessel.
7
Pressure parts may be in accordance with an ASME product standard
not covered by footnote 5, but such parts shall satisfy the requirements
applicable to a parts Manufacturer’s standard and footnote 6.
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2010 SECTION VIII — DIVISION 1
forwarded to the vessel Manufacturer and shall be available
to the Inspector.
(4) if heat treatment is performed at the plant of the
parts Manufacturer, certification by the parts Manufacturer
that such treatment was performed shall be accepted as
evidence of compliance with applicable Code paragraphs.
This certification shall be available to the Inspector.
(5) The Manufacturer of the vessel to be marked with
the Code Symbol shall be satisfied that the parts are suitable
for the design conditions specified for the completed vessel
in accordance with the rules of this Division and that the
requirements of (1), (2), (3), and (4) above have been met
for each welded standard pressure part.
The Manufacturer of the completed vessel or code
stamped part shall ensure that parts furnished under the
provisions of UG-11(a), UG-11(b), and UG-11(c) above
meet all of the applicable Code requirements such as UCS79(d), UNF-79(a), UHA-44(a), and UHT-79(a)(1).
(d) Parts furnished under the provisions of (a), (b), and
(c) above need not be manufactured by a Certificate of
Authorization Holder.
UG-12
UG-14
RODS AND BARS
(a) Rod and bar stock may be used in pressure vessel
construction for pressure parts such as flange rings, stiffening rings, frames for reinforced openings, stays and staybolts, and similar parts. Rod and bar materials shall
conform to the requirements for bars or bolting in the
applicable part of Subsection C.
(b) Except for flanges of all types, hollow cylindrically
shaped parts [up to and including NPS 4 (DN 100)] may
be machined from rod or bar, provided that the axial length
of the part is approximately parallel to the metal flow lines
of the stock. Other parts, such as heads or caps [up to and
including NPS 4 (DN 100)], not including flanges, may
be machined from rod or bar. Elbows, return bends, tees,
and header tees shall not be machined directly from rod
or bar.
UG-15
PRODUCT SPECIFICATION
When there is no material specification listed in Subsection C covering a particular wrought product of a grade,
but there is an approved specification listed in Subsection
C covering some other wrought product of that grade, the
product for which there is no specification may be used
provided:
(a) the chemical and physical properties, heat treating
requirements, and requirements for deoxidation, or grain
size requirements conform to the approved specification
listed in Subsection C. The stress values for that specification given in the tables referenced in UG-23 shall be used.
(b) the manufacturing procedures, tolerances, tests, and
marking are in accordance with a Section II specification
covering the same product form of a similar material;
(c) for the case of welded tubing made of plate, sheet,
or strip, without the addition of filler metal, the appropriate
stress values are multiplied by a factor of 0.85;
(d) the product is not pipe or tubing fabricated by fusion
welding with the addition of filler metal unless it is fabricated in accordance with the rules of this Division as a
pressure part;
(e) mill test reports reference the specifications used in
producing the material and in addition make reference to
this paragraph.
BOLTS AND STUDS
(a) Bolts and studs may be used for the attachment of
removable parts. Specifications, supplementary rules, and
maximum allowable stress values for acceptable bolting
materials are given in the tables referenced in UG-23.
(b) Studs shall be threaded full length or shall be
machined down to the root diameter of the thread in the
unthreaded portion, provided that the threaded portions are
at least 11⁄2 diameters in length.
Studs greater than eight diameters in length may have
an unthreaded portion that has the nominal diameter of the
thread, provided the following requirements are met:
(1) the threaded portions shall be at least 11⁄2 diameters
in length;
(2) the stud shall be machined down to the root diameter of the thread for a minimum distance of 0.5 diameters
adjacent to the threaded portion;
(3) a suitable transition shall be provided between
the root diameter and the unthreaded portion; and
(4) particular consideration shall be given to any
dynamic loadings.
DESIGN
UG-13
NUTS AND WASHERS
UG-16
(a) Nuts shall conform to the requirements in the applicable Part of Subsection C (see UCS-11 and UNF-13).
They shall engage the threads for the full depth of the nut.
(b) The use of washers is optional. When used, they
shall be of wrought materials.
GENERAL
(a) The design of pressure vessels and vessel parts shall
conform to the general design requirements in the following paragraphs and in addition to the specific requirements
for Design given in the applicable Parts of Subsections B
and C.
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(b) Minimum Thickness of Pressure Retaining Components. Except for the special provisions listed below, the
minimum thickness permitted for shells and heads, after
forming and regardless of product form and material, shall
be 1⁄16 in. (1.5 mm) exclusive of any corrosion allowance.
Exceptions are:
(1) the minimum thickness does not apply to heat
transfer plates of plate-type heat exchangers;
(2) this minimum thickness does not apply to the
inner pipe of double pipe heat exchangers nor to pipes and
tubes that are enclosed and protected from mechanical
damage by a shell, casing, or ducting, where such pipes
or tubes are NPS 6 (DN 150) and less. This exemption
applies whether or not the outer pipe, shell, or protective
element is constructed to Code rules. When the outer protective element is not provided by the Manufacturer as
part of the vessel, the Manufacturer shall note this on the
Manufacturer’s Data Report, and the owner or his designated agent shall be responsible to assure that the required
enclosures are installed prior to operation. Where pipes
and tubes are fully enclosed, consideration shall be given
to avoiding buildup of pressure within the protective chamber due to a tube/pipe leak. All other pressure parts of
these heat exchangers that are constructed to Code rules
must meet the 1⁄16 in. (1.5 mm) minimum thickness requirements.
(3) the minimum thickness of shells and heads of
unfired steam boilers shall be 1⁄4 in. (6 mm) exclusive of
any corrosion allowance;
(4) the minimum thickness of shells and heads used
in compressed air service, steam service, and water service,
made from materials listed in Table UCS-23, shall be 3⁄32
in. (2.5 mm) exclusive of any corrosion allowance.
(5) this minimum thickness does not apply to the
tubes in air cooled and cooling tower heat exchangers if
all the following provisions are met:
(a) the tubes shall not be used for lethal UW-2(a)
service applications;
(b) the tubes shall be protected by fins or other
mechanical means;
(c) the tube outside diameter shall be a minimum
of 3⁄8 in. (10 mm) and a maximum of 11⁄2 in. (38 mm);
(d) the minimum thickness used shall not be less
than that calculated by the formulas given in UG-27 or
1-1 and in no case less than 0.022 in. (0.5 mm).
(c) Mill Undertolerance. Plate material shall be ordered
not thinner than the design thickness. Vessels made of
plate furnished with an undertolerance of not more than
the smaller value of 0.01 in. (0.25 mm) or 6% of the
ordered thickness may be used at the full design pressure
for the thickness ordered. If the specification to which the
plate is ordered allows a greater undertolerance, the ordered
thickness of the materials shall be sufficiently greater than
the design thickness so that the thickness of the material
furnished is not more than the smaller of 0.01 in. (0.25 mm)
or 6% under the design thickness.
(d) Pipe Undertolerance. If pipe or tube is ordered by
its nominal wall thickness, the manufacturing undertolerance on wall thickness shall be taken into account except
for nozzle wall reinforcement area requirements in accordance with UG-37 and UG-40. The manufacturing undertolerances are given in the several pipe and tube
specifications listed in the applicable Tables in Subsection
C. After the minimum wall thickness is determined, it
shall be increased by an amount sufficient to provide the
manufacturing undertolerance allowed in the pipe or tube
specification.
(e) Corrosion Allowance in Design Formulas. The
dimensional symbols used in all design formulas throughout this Division represent dimensions in the corroded
condition.
UG-17
METHODS OF FABRICATION IN
COMBINATION
A vessel may be designed and constructed by a combination of the methods of fabrication given in this Division,
provided the rules applying to the respective methods of
fabrication are followed and the vessel is limited to the
service permitted by the method of fabrication having the
most restrictive requirements (see UG-116).
UG-18
MATERIALS IN COMBINATION
Except as specifically prohibited by other rules of this
Division, a vessel may be designed and constructed of
any combination of materials permitted in Subsection C,
provided the applicable rules are followed and the requirements in Section IX for welding dissimilar metals are met.
The requirements for the base metals, HAZ’s, and weld
metal(s) of a dissimilar metal weldment shall each be
applied in accordance with the rules of this Division. (For
example, if a carbon steel base metal is joined to a stainless
steel base metal with a nickel filler metal, the rules of Part
UCS apply to the carbon steel base metal and its HAZ,
Part UHA to the stainless steel base metal and its HAZ,
and Part UNF to the weld metal.)
NOTE: Because of the different thermal coefficients of expansion of
dissimilar materials, caution should be exercised in design and construction under the provisions of this paragraph in order to avoid difficulties
in service under extreme temperature conditions, or with unusual restraint
of parts such as may occur at points of stress concentration and also
because of metallurgical changes occurring at elevated temperatures. [See
also Galvanic Corrosion in Appendix A, A-440(c), of Section II, Part D.]
UG-19
SPECIAL CONSTRUCTIONS
(a) Combination Units. A combination unit is a pressure
vessel that consists of more than one independent pressure
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2010 SECTION VIII — DIVISION 1
chamber, operating at the same or different pressures and
temperatures. The parts separating each independent pressure chamber are the common elements. Each element,
including the common elements, shall be designed for at
least the most severe condition of coincident pressure and
temperature expected in normal operation (see 3-2). Only
the parts of chambers that come within the scope of this
Division, U-1, need be constructed in compliance with its
provisions. Also, see 9-1(c) for jacketed vessels.
UG-19(a)(1) Common Element Design. It is permitted to design each common element for a differential pressure less than the maximum of the design pressures of its
adjacent chambers (differential pressure design) or a mean
metal temperature less than the maximum of the design
temperatures of its adjacent chambers (mean metal temperature design), or both, only when the vessel is to be installed
in a system that controls the common element design conditions.
UG-19(a)(2) Differential Pressure Design. When
differential pressure design is permitted, the common element design pressure shall be the maximum differential
design pressure expected between the adjacent chambers.
The common element and its corresponding differential
pressure shall be indicated in the “Remarks” section of the
Manufacturer’s Data Report [see UG-120(b)(1) and UHX19.3] and marked on the vessel [see UG-116(j)(1)(a) and
UHX-19.2.1(a)]. The differential pressure shall be controlled to ensure the common element design pressure is
not exceeded.
UG-19(a)(3) Mean Metal Temperature Design.
When mean metal temperature design is used, the maximum common element design temperature determined in
accordance with UG-20(a) may be less than the greater of
the maximum design temperatures of its adjacent chambers; however, it shall not be less than the lower of the
maximum design temperatures of its adjacent chambers.
The common element and its corresponding design temperature shall be indicated in the “Remarks” section of the
Manufacturer’s Data Report [see UG-120(b)(2) and
UHX-19.3] and marked on the vessel [see UG-116(j)(1)(b)
and UHX-19.2.1(b)]. The fluid temperature, flow, and pressure, as required, shall be controlled to ensure the common
element design temperature is not exceeded.
(b) Special Shapes. Vessels other than cylindrical and
spherical and those for which no design rules are provided
in this Division may be designed under the conditions set
forth in U-2.
(c) When no design rules are given and the strength of
a pressure vessel or vessel part cannot be calculated with a
satisfactory assurance of accuracy, the maximum allowable
working pressure of the completed vessel shall be established in accordance with the provisions of UG-101.
UG-20
DESIGN TEMPERATURE
(a) Maximum. Except as required in UW-2(d)(3), the
maximum temperature used in design shall be not less
than the mean metal temperature (through the thickness)
expected under operating conditions for the part considered
(see 3-2). If necessary, the metal temperature shall be determined by computation or by measurement from equipment
in service under equivalent operating conditions. See also
U-2(a).
(b) Minimum. The minimum metal temperature used in
design shall be the lowest expected in service except when
lower temperatures are permitted by the rules of this Division (see UCS-66, UCS-160, and footnote 37, UG-116).
The minimum mean metal temperature shall be determined
by the principles described in (a) above. Consideration
shall include the lowest operating temperature, operational
upsets, autorefrigeration, atmospheric temperature, and any
other sources of cooling [except as permitted in (f)(3)
below for vessels meeting the requirements of (f) below].
The MDMT marked on the nameplate shall correspond to
a coincident pressure equal to the MAWP. When there
are multiple MAWP’s, the largest value shall be used to
establish the MDMT marked on the nameplate. Additional
MDMT’s corresponding with other MAWP’s may also be
marked on the nameplate (see footnote 37).
(c) Design temperatures that exceed the temperature
limit in the applicability column shown in Section II, Part
D, Subpart 1, Tables 1A, 1B, and 3 are not permitted. In
addition, design temperatures for vessels under external
pressure shall not exceed the maximum temperatures given
on the external pressure charts.
(d) The design of zones with different metal temperatures may be based on their determined temperatures.
(e) Suggested methods for obtaining the operating temperature of vessel walls in service are given in Appendix C.
(f) Impact testing per UG-84 is not mandatory for pressure vessel materials that satisfy all of the following:
(1) The material shall be limited to P-No. 1, Gr. No.
1 or 2, and the thickness, as defined in UCS-66(a) [see
also Note (1) in Fig. UCS-66.2], shall not exceed that given
in (a) or (b) below:
(a) 1⁄2 in. (13 mm) for materials listed in Curve A
of Fig. UCS-66;
(b) 1 in. (25 mm) for materials listed in Curve B,
C, or D of Fig. UCS-66.
(2) The completed vessel shall be hydrostatically
tested per UG-99(b) or (c) or 27-4.
(3) Design temperature is no warmer than 650°F
(345°C) nor colder than −20°F (−29°C). Occasional
operating temperatures colder than −20°F (−29°C) are
acceptable when due to lower seasonal atmospheric temperature.
(4) The thermal or mechanical shock loadings are not
a controlling design requirement. (See UG-22.)
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2010 SECTION VIII — DIVISION 1
(5) Cyclical loading is not a controlling design
requirement. (See UG-22.)
UG-21
vessel constructed under these rules. The maximum allowable tensile stress values permitted for different materials
are given in Subpart 1 of Section II, Part D. Section II,
Part D is published as two separate publications. One publication contains values only in the U.S. Customary units
and the other contains values only in SI units. The selection
of the version to use is dependent on the set of units selected
for construction. A listing of these materials is given in
the following tables, which are included in Subsection C.
For material identified as meeting more than one material
specification and /or grade, the maximum allowable tensile
stress value for either material specification and /or grade
may be used provided all requirements and limitations
for the material specification and grade are met for the
maximum allowable tensile stress value chosen.
DESIGN PRESSURE8
Each element of a pressure vessel shall be designed for
at least the most severe condition of coincident pressure
(including coincident static head in the operating position)
and temperature expected in normal operation. For this
condition, the maximum difference in pressure between
the inside and outside of a vessel, or between any two
chambers of a combination unit, shall be considered [see
UG-98 and 3-2]. See also U-2(a).
UG-22
Table UCS-23 Carbon and Low Alloy Steel (stress values
in Section II, Part D, Table 3 for bolting, and Table 1A
for other carbon steels)
Table UNF-23 Nonferrous Metals (stress values in Section
II, Part D, Table 3 for bolting, and Table 1B for other
nonferrous metals)
Table UHA-23 High Alloy Steel (stress values in Section
II, Part D, Table 3 for bolting, and Table 1A for other
high alloy steels)
Table UCI-23 Maximum Allowable Stress Values in Tension for Cast Iron
Table UCD-23 Maximum Allowable Stress Values in Tension for Cast Ductile Iron
Table UHT-23 Ferritic Steels with Properties Enhanced
by Heat Treatment (stress values in Section II, Part D,
Table 1A)
Table ULT-23 Maximum Allowable Stress Values in Tension for 5%, 8%, and 9% Nickel Steels and 5083-0
Aluminum Alloy at Cryogenic Temperatures for Welded
and Nonwelded Construction
LOADINGS
The loadings to be considered in designing a vessel shall
include those from:
(a) internal or external design pressure (as defined in
UG-21);
(b) weight of the vessel and normal contents under
operating or test conditions;
(c) superimposed static reactions from weight of
attached equipment, such as motors, machinery, other vessels,piping, linings, and insulation;
(d) the attachment of:
(1) internals (see Appendix D);
(2) vessel supports, such as lugs, rings, skirts, saddles,
and legs (see Appendix G);
(e) cyclic and dynamic reactions due to pressure or thermal variations, or from equipment mounted on a vessel,
and mechanical loadings;
(f) wind, snow, and seismic reactions, where required;
(g) impact reactions such as those due to fluid shock;
(h) temperature gradients and differential thermal
expansion;
(i) abnormal pressures, such as those caused by deflagration;
(j) test pressure and coincident static head acting during
the test (see UG-99).
UG-23
(b) The maximum allowable longitudinal compressive
stress to be used in the design of cylindrical shells or tubes,
either seamless or butt welded, subjected to loadings that
produce longitudinal compression in the shell or tube shall
be the smaller of the following values:
(1) the maximum allowable tensile stress value permitted in (a) above;
(2) the value of the factor B determined by the following procedure where
MAXIMUM ALLOWABLE STRESS
VALUES9
E p modulus of elasticity of material at design temperature. The modulus of elasticity to be used shall
be taken from the applicable materials chart in
Section II, Part D, Subpart 3. (Interpolation may
be made between lines for intermediate temperatures.)
Ro p outside radius of cylindrical shell or tube
t p the minimum required thickness of the cylindrical
shell or tube
(a) The maximum allowable stress value is the maximum unit stress permitted in a given material used in a
8
It is recommended that a suitable margin be provided above the
pressure at which the vessel will be normally operated to allow for
probable pressure surges in the vessel up to the setting of the pressure
relieving devices (see UG-134).
9
For the basis on which the tabulated stress values have been established, see Appendix 1 of Section II, Part D.
16
2010 SECTION VIII — DIVISION 1
operation10 of the vessel, the induced maximum general
primary membrane stress does not exceed the maximum
allowable stress value in tension (see UG-23), except as
provided in (d) below. Except where limited by special
rules, such as those for cast iron in flanged joints, the
above loads shall not induce a combined maximum primary
membrane stress plus primary bending stress across the
thickness that exceeds 11⁄2 times11 the maximum allowable
stress value in tension (see UG-23). It is recognized that
high localized discontinuity stresses may exist in vessels
designed and fabricated in accordance with these rules.
Insofar as practical, design rules for details have been
written to limit such stresses to a safe level consistent with
experience.
The maximum allowable stress values that are to be
used in the thickness calculations are to be taken from the
tables at the temperature that is expected to be maintained
in the metal under the conditions of loading being considered. Maximum stress values may be interpolated for intermediate temperatures.
(d) For the combination of earthquake loading, or wind
loading with other loadings in UG-22, the wall thickness
of a vessel computed by these rules shall be determined
such that the general primary membrane stress shall not
exceed 1.2 times the maximum allowable stress permitted
in (a), (b), or (c) above. This rule is applicable to stresses
caused by internal pressure, external pressure, and axial
compressive load on a cylinder.12
Earthquake loading and wind loading need not be considered to act simultaneously.
(e) Localized discontinuity stresses [see (c) above] are
calculated in Appendix 1, 1-5(g) and 1-8(e), Part UHX,
and Appendix 5. The primary plus secondary stresses11 at
these discontinuities shall be limited to SPS, where SPS p
3S, and S is the maximum allowable stress of the material
at temperature [see (a) above].
In lieu of using SPS p 3S, a value of SPS p 2SY may
be used, where SY is the yield strength at temperature,
provided the following are met:
(1) the allowable stress of material S is not governed
by time-dependent properties as provided in Tables 1A or
1B of Section II, Part D;
The joint efficiency for butt welded joints shall be taken
as unity.
The value of B shall be determined as follows.
Step 1. Using the selected values of t and R, calculate
the value of factor A using the following formula:
Ap
0.125
(Ro / t)
Step 2. Using the value of A calculated in Step 1, enter
the applicable material chart in Section II, Part D, Subpart
3 for the material under consideration. Move vertically to
an intersection with the material/temperature line for the
design temperature (see UG-20). Interpolation may be
made between lines for intermediate temperatures. If tabular values in Subpart 3 of Section II, Part D are used, linear
interpolation or any other rational interpolation method
may be used to determine a B value that lies between two
adjacent tabular values for a specific temperature. Such
interpolation may also be used to determine a B value at
an intermediate temperature that lies between two sets of
tabular values, after first determining B values for each set
of tabular values.
In cases where the value at A falls to the right of the
end of the material /temperature line, assume an intersection with the horizontal projection of the upper end of the
material /temperature line. If tabular values are used, the
last (maximum) tabulated value shall be used. For values
of A falling to the left of the material /temperature line,
see Step 4.
Step 3. From the intersection obtained in Step 2, move
horizontally to the right and read the value of factor B.
This is the maximum allowable compressive stress for the
values of t and Ro used in Step 1.
Step 4. For values of A falling to the left of the applicable
material /temperature line, the value of B shall be calculated
using the following formula:
Bp
AE
2
If tabulated values are used, determine B as in Step 2
and apply it to the equation in Step 4.
Step 5. Compare the value of B determined in Steps 3
or 4 with the computed longitudinal compressive stress in
the cylindrical shell or tube, using the selected values of
t and Ro. If the value of B is smaller than the computed
compressive stress, a greater value of t must be selected
and the design procedure repeated until a value of B is
obtained that is greater than the compressive stress computed for the loading on the cylindrical shell or tube.
(c) The wall thickness of a vessel computed by these
rules shall be determined such that, for any combination
of loadings listed in UG-22 that induce primary stress
and are expected to occur simultaneously during normal
10
See 3-2 Definition of Terms.
The user of the Code is cautioned that for elevated metal temperatures
when high membrane stress and /or high bending stress exist in the section,
some inelastic straining due to creep in excess of the limits allowed by
the criteria of Appendix 1 of Section II, Part D may occur.
12
UG-23(d) permits an increase in allowable stress when earthquake
or wind loading is considered in combination with other loads and pressure
defined in UG-22. The 1.2 increase permitted is equivalent to a load
reduction factor of 0.833. Some standards which define applicable load
combinations do not permit an increase in allowable stress, however a
load reduction factor (typically 0.75) is applied to multiple transient loads
(e.g., wind plus live load, seismic plus live load, etc.).
11
17
2010 SECTION VIII — DIVISION 1
(2) the room temperature ratio of the specified minimum yield strength to specified minimum tensile strength
for the material does not exceed 0.7;
(3) the value for SY at temperature can be obtained
from Table Y-1 of Section II, Part D.
UG-24
in tubesheets drilled with holes spaced no farther apart
than the wall thickness of the casting. The examination
afforded may be taken in lieu of destructive or radiographic
testing required in (2)(b) above.
(5) For carbon, low alloy, or high alloy steels, higher
quality factors may be applied if in addition to the minimum
requirements of (a)(1) above, additional examinations are
made as follows.
(a) For centrifugal castings, a factor not to exceed
90% may be applied if the castings are examined by the
magnetic particle or liquid penetrant methods in accordance
with the requirements of Appendix 7.
(b) For static and centrifugal castings a factor not
to exceed 100% may be applied if the castings are examined
in accordance with all of the requirements of Appendix 7.
(6) The following additional requirements apply
when castings (including those permitted in UG-11) are to
be used in vessels to contain lethal substances (UW-2).
(a) Castings of cast iron (UCI-2) and cast ductile
iron (UCD-2) are prohibited.
(b) Each casting of nonferrous material permitted
by this Division shall be radiographed at all critical sections
(see footnote 1, Appendix 7) without revealing any defects.
The quality factor for nonferrous castings for lethal service
shall not exceed 90%.
(c) Each casting of steel material permitted by this
Division shall be examined per Appendix 7 for severe
service applications [7-3(b)]. The quality factor for lethal
service shall not exceed 100%.
(b) Defects. Imperfections defined as unacceptable by
either the material specification or by Appendix 7, 7-3,
whichever is more restrictive, are considered to be defects
and shall be the basis for rejection of the casting. Where
defects have been repaired by welding, the completed
repair shall be subject to reexamination and, when required
by either the rules of this Division or the requirements of
the castings specification, the repaired casting shall be
postweld heat treated and, to obtain a 90% or 100% quality
factor, the repaired casting shall be stress relieved.
(c) Identification and Marking. Each casting to which
a quality factor greater than 80% is applied shall be marked
with the name, trademark, or other traceable identification
of the manufacturer and the casting identification, including
the casting quality factor and the material designation.
CASTINGS
(a) Quality Factors. A casting quality factor as specified
below shall be applied to the allowable stress values for
cast materials given in Subsection C except for castings
permitted by Part UCI. At a welded joint in a casting, only
the lesser of the casting quality factor or the weld joint
efficiency specified in UW-12 applies, but not both. NDE
methods and acceptance standards are given in Appendix 7.
(1) A factor not to exceed 80% shall be applied to
static castings that are examined in accordance with the
minimum requirements of the material specification. In
addition to the minimum requirements of the material specification, all surfaces of centrifugal castings shall be
machined after heat treatment to a finish not coarser than
250 in. (6.3 m) arithmetical average deviation, and a
factor not to exceed 85% shall be applied.
(2) For nonferrous and ductile cast iron materials, a
factor not to exceed 90% shall be applied if in addition to
the minimum requirements of UG-24(a)(1):
(a) each casting is subjected to a thorough examination of all surfaces, particularly such as are exposed by
machining or drilling, without revealing any defects;
(b) at least three pilot castings13 representing the
first lot of five castings made from a new or altered design
are sectioned or radiographed at all critical sections (see
footnote 1, Appendix 7) without revealing any defects;
(c) one additional casting taken at random from
every subsequent lot of five is sectioned or radiographed
at all critical sections without revealing any defects; and
(d) all castings other than those that have been
radiographed are examined at all critical sections by the
magnetic particle or liquid penetrant methods in accordance
with the requirements of Appendix 7.
(3) For nonferrous and ductile cast iron materials, a
factor not to exceed 90% may be used for a single casting
that has been radiographed at all critical sections and found
free of defects.
(4) For nonferrous and ductile cast iron materials, a
factor not to exceed 90% may be used for a casting that
has been machined to the extent that all critical sections
are exposed for examination for the full wall thickness; as
UG-25
CORROSION
(a) The user or his designated agent (see U-2) shall
specify corrosion allowances other than those required by
the rules of this Division. Where corrosion allowances are
not provided, this fact shall be indicated on the Data Report.
(b) Vessels or parts of vessels subject to thinning by
corrosion, erosion, or mechanical abrasion shall have provision made for the desired life of the vessel by a suitable
13
Pilot casting — Any one casting, usually one of the first from a
new pattern, poured of the same material and using the identical foundry
procedure (risering, gating, pouring, and melting) as the castings it is
intended to represent. Any pilot casting or castings taken to represent a
lot and the castings of that lot shall be poured from a heat of metal from
which the castings on the current order are poured.
18
2010 SECTION VIII — DIVISION 1
increase in the thickness of the material over that determined by the design formulas, or by using some other
suitable method of protection. (See Appendix E.)
(b) The symbols defined below are used in the formulas
of this paragraph.
E p joint efficiency for, or the efficiency of, appropriate joint in cylindrical or spherical shells, or
the efficiency of ligaments between openings,
whichever is less.
For welded vessels, use the efficiency specified
in UW-12.
For ligaments between openings, use the efficiency calculated by the rules given in UG-53.
P p internal design pressure (see UG-21)
R p inside radius of the shell course under consideration,15
S p maximum allowable stress value (see UG-23 and
the stress limitations specified in UG-24)
t p minimum required thickness of shell
NOTE: When using high alloys and nonferrous materials either for solid
wall or clad or lined vessels, refer to UHA-6, UCL-3, and UNF-4, as
appropriate.
(c) Material added for these purposes need not be of
the same thickness for all parts of the vessel if different
rates of attack are expected for the various parts.
(d) No additional thickness need be provided when previous experience in like service has shown that corrosion
does not occur or is of only a superficial nature.
(e) Telltale Holes. Telltale holes may be used to provide
some positive indication when the thickness has been
reduced to a dangerous degree. Telltale holes shall not be
used in vessels that are to contain lethal substances [see
UW-2(a)], except as permitted by ULW-76 for vent holes
in layered construction. When telltale holes are provided,
they shall have a diameter of 1⁄16 in. to 3⁄16 in. (1.5 mm to
5 mm) and have a depth not less than 80% of the thickness
required for a seamless shell of like dimensions. These
holes shall be provided in the opposite surface to that where
deterioration is expected. [For telltale holes in clad or lined
vessels, see UCL-25(b).]
(f) Openings for Drain. Vessels subject to corrosion
shall be supplied with a suitable drain opening at the lowest
point practicable in the vessel; or a pipe may be used
extending inward from any other location to within 1⁄4 in.
(6 mm) of the lowest point.
UG-26
(c) Cylindrical Shells. The minimum thickness or maximum allowable working pressure of cylindrical shells shall
be the greater thickness or lesser pressure as given by (1)
or (2) below.
(1) Circumferential Stress (Longitudinal Joints).
When the thickness does not exceed one-half of the inside
radius, or P does not exceed 0.385SE, the following formulas shall apply:
tp
(1)
(2) Longitudinal Stress (Circumferential Joints).16
When the thickness does not exceed one-half of the inside
radius, or P does not exceed 1.25SE, the following formulas
shall apply:
LININGS
tp
Corrosion resistant or abrasion resistant linings, whether
or not attached to the wall of a vessel, shall not be considered as contributing to the strength of the wall except as
permitted in Part UCL (see Appendix F).
UG-27
PR
SEt
or P p
SE − 0.6P
R + 0.6t
PR
2SEt
or P p
2SE + 0.4P
R − 0.4t
(2)
(d) Spherical Shells. When the thickness of the shell of
a wholly spherical vessel does not exceed 0.356R, or P
does not exceed 0.665SE, the following formulas shall
apply:
THICKNESS OF SHELLS UNDER
INTERNAL PRESSURE
tp
(a) The minimum required thickness of shells under
internal pressure shall not be less than that computed by
the following formulas,14 except as permitted by Appendix
1 or 32. In addition, provision shall be made for any of
the loadings listed in UG-22, when such loadings are
expected. The provided thickness of the shells shall also
meet the requirements of UG-16, except as permitted in
Appendix 32.
PR
2SEt
or P p
2SE − 0.2P
R + 0.2t
(3)
(e) When necessary, vessels shall be provided with stiffeners or other additional means of support to prevent
overstress or large distortions under the external loadings
listed in UG-22 other than pressure and temperature.
15
For pipe, the inside radius R is determined by the nominal outside
radius minus the nominal wall thickness.
16
These formulas will govern only when the circumferential joint
efficiency is less than one-half the longitudinal joint efficiency, or when
the effect of supplementary loadings (UG-22) causing longitudinal bending or tension in conjunction with internal pressure is being investigated.
An example illustrating this investigation is given in L-2.1 and L-2.2.
14
Formulas in terms of the outside radius and for thicknesses and
pressures beyond the limits fixed in this paragraph are given in 1-1 to
1-3.
19
2010 SECTION VIII — DIVISION 1
FIG. UG-28 DIAGRAMMATIC REPRESENTATION OF VARIABLES FOR DESIGN OF CYLINDRICAL VESSELS
SUBJECTED TO EXTERNAL PRESSURE
(f) A stayed jacket shell that extends completely around
a cylindrical or spherical vessel shall also meet the requirements of UG-47(c).
(g) Any reduction in thickness within a shell course or
spherical shell shall be in accordance with UW-9.
UG-28
Lp
THICKNESS OF SHELLS AND TUBES
UNDER EXTERNAL PRESSURE
(a) Rules for the design of shells and tubes under external pressure given in this Division are limited to cylindrical
shells, with or without stiffening rings, tubes, and spherical
shells. Three typical forms of cylindrical shells are shown
in Fig. UG-28. Charts used in determining minimum
required thicknesses of these components are given in Subpart 3 of Section II, Part D.
(b) The symbols defined below are used in the procedures of this paragraph:
A p factor determined from Fig. G in Subpart 3 of
Section II, Part D and used to enter the applicable
material chart in Subpart 3 of Section II, Part D.
For the case of cylinders having Do /t values less
than 10, see UG-28(c)(2).
B p factor determined from the applicable material
chart or table in Subpart 3 of Section II, Part
D for maximum design metal temperature [see
UG-20(c)]
Do p outside diameter of cylindrical shell course or tube
E p modulus of elasticity of material at design temperature. For external pressure design in accordance
with this Section, the modulus of elasticity to be
Pp
Pa p
Ro p
tp
ts p
used shall be taken from the applicable materials
chart in Subpart 3 of Section II, Part D. (Interpolation may be made between lines for intermediate
temperatures.)
total length, in. (mm), of a tube between tubesheets, or design length of a vessel section
between lines of support (see Fig. UG-28.1). A
line of support is:
(1) a circumferential line on a head (excluding
conical heads) at one-third the depth of the head
from the head tangent line as shown on Fig.
UG-28;
(2) a stiffening ring that meets the requirements of UG-29;
(3) a jacket closure of a jacketed vessel that
meets the requirements of 9-5;
(4) a cone-to-cylinder junction or a knuckleto-cylinder junction of a toriconical head or section that satisfies the moment of inertia requirement of 1-8.
external design pressure [see Note in UG-28(f)]
calculated value of maximum allowable external
working pressure for the assumed value of t, [see
Note in (f) below]
outside radius of spherical shell
minimum required thickness of cylindrical shell
or tube, or spherical shell, in. (mm)
nominal thickness of cylindrical shell or tube,
in. (mm)
(c) Cylindrical Shells and Tubes. The required minimum thickness of a cylindrical shell or tube under external
20
2010 SECTION VIII — DIVISION 1
FIG. UG-28.1 DIAGRAMMATIC REPRESENTATION OF LINES OF SUPPORT FOR DESIGN OF CYLINDRICAL
VESSELS SUBJECTED TO EXTERNAL PRESSURE
NOTES:
(1) When the cone-to-cylinder or the knuckle-to-cylinder junction is not a line of support, the nominal thickness of the cone, knuckle, or toriconical
section shall not be less than the minimum required thickness of the adjacent cylindrical shell. Also, the reinforcement requirement of 1-8
shall be satisfied when a knuckle is not provided at the cone-to-cylinder junction.
(2) Calculations shall be made using the diameter and corresponding thickness of each cylindrical section with dimension L as shown. Thicknesses
of the transition sections are based on Note (1).
(3) When the cone-to-cylinder or the knuckle-to-cylinder junction is a line of support, the moment of inertia shall be provided in accordance with
1-8 [see UG-33(f)].
21
(10)
2010 SECTION VIII — DIVISION 1
pressure, either seamless or with longitudinal butt joints,
shall be determined by the following procedure:
(1) Cylinders having Do /t values ≥ 10:
Step 1. Assume a value for t and determine the ratios
L /Do and Do /t.
Step 2. Enter Fig. G in Subpart 3 of Section II, Part D
at the value of L /Do determined in Step 1. For values of
L /Do greater than 50, enter the chart at a value of L /Do p
50. For values of L /Do less than 0.05, enter the chart at a
value of L /Do p 0.05.
Step 3. Move horizontally to the line for the value of
Do /t determined in Step 1. Interpolation may be made for
intermediate values of Do /t; extrapolation is not permitted.
From this point of intersection move vertically downward
to determine the value of factor A.
Step 4. Using the value of A calculated in Step 3, enter
the applicable material chart in Subpart 3 of Section II,
Part D for the material under consideration. Move vertically
to an intersection with the material /temperature line for
the design temperature (see UG-20). Interpolation may be
made between lines for intermediate temperatures. If tabular values in Subpart 3 of Section II, Part D are used, linear
interpolation or any other rational interpolation method
may be used to determine a B value that lies between two
adjacent tabular values for a specific temperature. Such
interpolation may also be used to detemine a B value at
an intermediate temperature that lies between two sets of
tabular values, after first determining B values for each set
of tabular values.
In cases where the value of A falls to the right of the
end of the material /temperature line, assume an intersection with the horizontal projection of the upper end of the
material /temperature line. If tabular values are used, the
last (maximum) tabulated value shall be used. For values
of A falling to the left of the material /temperature line,
see Step 7.
Step 5. From the intersection obtained in Step 4, move
horizontally to the right and read the value of factor B.
Step 6. Using this value of B, calculate the value of the
maximum allowable external working pressure Pa using
the following formula:
Pa p
value for t and repeat the design procedure until a value
of Pa is obtained that is equal to or greater than P. An
example illustrating the use of this procedure is given in
L-3(a).
(2) Cylinders having Do /t values <10:
Step 1. Using the same procedure as given in
UG-28(c)(1), obtain the value of B. For values of Do /t less
than 4, the value of factor A can be calculated using the
following formula:
Ap
(Do / t )2
For values of A greater than 0.10, use a value of 0.10.
Step 2. Using the value of B obtained in Step 1, calculate
a value Pa1 using the following formula:
Pa1 p
冤(D / t ) − 0.0833冥 B
2.167
o
Step 3. Calculate a value P a2 using the following
formula:
Pa2 p
冤
2S
1
1−
Do / t
Do / t
冥
where S is the lesser of two times the maximum allowable
stress value in tension at design metal temperature, from
the applicable table referenced in UG-23, or 0.9 times the
yield strength of the material at design temperature. Values
of yield strength are obtained from the applicable external
pressure chart as follows:
(a) For a given temperature curve, determine the
B value that corresponds to the right hand side termination
point of the curve.
(b) The yield strength is twice the B value obtained
in (a) above.
Step 4. The smaller of the values of Pa1 calculated in
Step 2, or Pa2 calculated in Step 3 shall be used for the
maximum allowable external working pressure Pa. Compare Pa with P. If Pa is smaller than P, select a larger value
for t and repeat the design procedure until a value for Pa
is obtained that is equal to or greater than P.
(d) Spherical Shells. The minimum required thickness
of a spherical shell under external pressure, either seamless
or of built-up construction with butt joints, shall be determined by the following procedure:
Step 1. Assume a value for t and calculate the value of
factor A using the following formula:
4B
3(Do / t )
Step 7. For values of A falling to the left of the applicable
material /temperature line, the value of Pa can be calculated
using the following formula:
Pa p
1.1
2AE
3(Do / t )
Ap
If tabular values are used, determine B as in Step 4 and
apply it to the equation in Step 6.
Step 8. Compare the calculated value of Pa obtained in
Steps 6 or 7 with P. If Pa is smaller than P, select a larger
0.125
(Ro / t)
Step 2. Using the value of A calculated in Step 1, enter
the applicable material chart in Subpart 3 of Section II,
Part D for the material under consideration. Move vertically
to an intersection with the material /temperature line for
22
2010 SECTION VIII — DIVISION 1
the design temperature (see UG-20). Interpolation may be
made between lines for intermediate temperatures. If tabular values in Subpart 3 of Section II, Part D are used, linear
interpolation or any other rational interpolation method
may be used to detemine a B value that lies between two
adjacent tabular values for a specific temperature. Such
interpolation may also be used to determine a B value at
an intermediate temperature that lies between two sets of
tabular values, after first detemining B values for each set
of tabular values.
In cases where the value at A falls to the right of the
end of the material /temperature line, assume an intersection with the horizontal projection of the upper end of the
material /temperature line. If tabular values are used, the
last (maximum) tabulated value shall be used. For values
at A falling to the left of the material /temperature line, see
Step 5.
Step 3. From the intersection obtained in Step 2, move
horizontally to the right and read the value of factor B.
Step 4. Using the value of B obtained in Step 3, calculate
the value of the maximum allowable external working
pressure Pa using the following formula:
Pa p
stamped with the maximum allowable external working
pressure.
(g) When there is a longitudinal lap joint in a cylindrical
shell or any lap joint in a spherical shell under external
pressure, the thickness of the shell shall be determined by
the rules in this paragraph, except that 2P shall be used
instead of P in the calculations for the required thickness.
(h) Circumferential joints in cylindrical shells may be
of any type permitted by the Code and shall be designed
for the imposed loads.
(i) Those portions of pressure chambers of vessels that
are subject to a collapsing pressure and that have a shape
other than that of a complete circular cylinder or formed
head, and also jackets of cylindrical vessels that extend
over only a portion of the circumference, shall be fully
staybolted in accordance with the requirements of UG-47
through UG-50 or shall be proof tested in compliance with
UG-101(p).
(j) When necessary, vessels shall be provided with stiffeners or other additional means of support to prevent
overstress or large distortions under the external loadings
listed in UG-22 other than pressure and temperature.
B
(Ro / t)
UG-29
Step 5. For values of A falling to the left of the applicable
material /temperature line, the value of Pa can be calculated
using the following formula:
Pa p
STIFFENING RINGS FOR
CYLINDRICAL SHELLS UNDER
EXTERNAL PRESSURE
(a) External stiffening rings shall be attached to the
shell by welding or brazing [see UG-30]. Internal stiffening
rings need not be attached to the shell when the rings are
designed to carry the loads and adequate means of support
is provided to hold the ring in place when subjected to
external pressure loads. Segments of rings need not be
attached when the requirements of UG-29(c) are met.
Except as exempted in (f) below, the available moment
of inertia of a circumferential stiffening ring shall be not
less than that determined by one of the following two
formulas:
0.0625E
(Ro / t )2
If tabulated values are used, determine B as in Step 2
and apply it to the equation in Step 4.
Step 6. Compare Pa obtained in Steps 4 or 5 with P. If
Pa is smaller than P, select a larger value for t and repeat
the design procedure until a value for Pa is obtained that
is equal to or greater than P. An example illustrating the
use of this procedure is given in L-3(b).
(e) The external design pressure or maximum allowable
external working pressure shall not be less than the maximum expected difference in operating pressure that may
exist between the outside and the inside of the vessel at
any time.
(f) Vessels intended for service under external design
pressures of 15 psi (100 kPa) and less [see U-1(c)(2)(h)]
may be stamped with the Code Symbol denoting compliance with the rules for external pressure provided all the
applicable rules of this Division are satisfied. When the
Code Symbol is to be applied, the user or his designated
agent shall specify the required maximum allowable external working pressure.17 The vessel shall be designed and
Is p [Do2 Ls (t + As / Ls )A ] / 14
Is′ p[Do2 Ls (t + As / Ls )A] / 10.9
Is p required moment of inertia of the stiffening ring
cross section about its neutral axis parallel to the
axis of the shell
Is′ p required moment of inertia of the combined ringshell cross section about its neutral axis parallel
to the axis of the shell
I p available moment of inertia of the stiffening ring
cross section about its neutral axis parallel to the
axis of the shell
I ′ p available moment of inertia of combined ringshell cross section about its neutral axis parallel
to the axis of the shell. The nominal shell thickness
17
It is recommended that a suitable margin be provided when establishing the maximum allowable external working pressure to allow for pressure variations in service.
23
2010 SECTION VIII — DIVISION 1
ts shall be used and the width of shell that is taken
as contributing to the moment of inertia of the
combined section shall not be greater than 1.10
interpolation method may be used to determine an A value
that lies between two adjacent tabular values for a specific
temperature. Linear interpolation may also be used to determine an A value at an intermediate temperature that lies
between two sets of tabular values, after first determining
A values for each set of tabular values. The value of A so
determined is then applied in the equation for I or Is′ in
Steps 6a or 6b.
Step 2b. If material charts in Subpart 3 of Section II,
Part D are used, enter the right-hand side of the applicable
material chart for the material under consideration at the
value of B determined by Step 1. If different materials are
used for the shell and stiffening ring, use the material chart
resulting in the larger value of A in Step 4, below.
Step 3. Move horizontally to the left to the
material /temperature line for the design metal temperature.
For values of B falling below the left end of the
material /temperature line, see Step 5.
Step 4. Move vertically to the bottom of the chart and
read the value of A.
Step 5. For values of B falling below the left end of the
material /temperature line for the design temperature, the
value of A can be calculated using the formula A p 2B /E.
Step 6a. In those cases where only the stiffening ring is
considered, compute the required moment of inertia from
the formula for Is given above.
Step 6b. In those cases where the combined ring-shell
is considered, compute the required moment of inertia from
the formula for Is′ given above.
Step 7a. In those cases where only the stiffening ring is
considered, determine the available moment of inertia I as
given in the definitions.
Step 7b. In those cases where the combined ring-shell
is considered, determine the available moment of inertia
I′ as given in the definitions.
冪Dots and shall be taken as lying one-half on each
side of the centroid of the ring. Portions of the
shell plate shall not be considered as contributing
area to more than one stiffening ring.
CAUTIONARY NOTE: Stiffening rings may be subject to lateral buckling. This should be considered in addition to the requirements for Is and
I′s [see U-2(g)].
If the stiffeners should be so located that the maximum
permissible effective shell sections overlap on either or
both sides of a stiffener, the effective shell section for that
stiffener shall be shortened by one-half of each overlap.
As p cross-sectional area of the stiffening ring
A p factor determined from the applicable chart in
Subpart 3 of Section II, Part D for the material
used in the stiffening ring, corresponding to the
factor B, below, and the design temperature for
the shell under consideration
B p factor determined from the applicable chart or
table in Subpart 3 of Section II, Part D for the
material used for the stiffening ring [see
UG-20(c)]
Ls p one-half of the distance from the centerline of the
stiffening ring to the next line of support on one
side, plus one-half of the centerline distance to
the next line of support on the other side of the
stiffening ring, both measured parallel to the axis
of the cylinder. A line of support is:
(a) a stiffening ring that meets the requirements of this paragraph;
(b) a circumferential connection to a jacket for
a jacketed section of a cylindrical shell;
(c) a circumferential line on a head at one-third
the depth of the head from the head tangent line
as shown on Fig. UG-28;
(d) a cone-to-cylinder junction.
NOTE: In those cases where the stiffening ring is not attached to the
shell or where the stiffening ring is attached but the designer chooses to
consider only the ring, Step 6a and Step 7a are considered. In those cases
where the stiffening ring is attached to the shell and the combined moment
of inertia is considered, Step 6b and Step 7b are considered.
Do, E, P, t, and ts are as defined in UG-28(b).
The adequacy of the moment of inertia for a stiffening
ring shall be determined by the following procedure.
Step 1. Assuming that the shell has been designed and
Do, Ls, and t are known, select a member to be used for
the stiffening ring and determine its cross-sectional area
As. Then calculate factor B using the following formula:
B p 3/4
Step 8. If the required moment of inertia is greater than
the available moment of inertia for the section selected,
for those cases where the stiffening ring is not attached or
where the combined ring-shell stiffness was not considered,
a new section with a larger moment of inertia must be
selected; the ring must be attached to the shell and the
combination shall be considered; or the ring-shell combination that was previously not considered together shall be
considered together. If the required moment of inertia is
greater than the available moment of inertia for those cases
where the combined ring-shell was considered, a new ring
section with a larger moment of inertia must be selected.
冢t + A / L 冣
PDo
s
s
Step 2a. If tabular values in Subpart 3 of Section II,
Part D are used, linear interpolation or any other rational
24
2010 SECTION VIII — DIVISION 1
stiffening rings, should be supported through the medium of substantial
members extending over at least one-third of the circumference, as shown
at (K) in Fig. UG-29.1.
Attention is called also to the hazard of imposing highly concentrated
loads by the improper support of one vessel on another or by the hanging
or supporting of heavy weights directly on the shell of the vessel. (See
Appendix G.)
In any case, when a new section is used, all of the calculations shall be repeated using the new section properties of
the ring or ring-shell combination.
If the required moment of inertia is smaller than the
actual moment of inertia of the ring or ring-shell combination, whichever is used, that ring section or combined
section is satisfactory.
An example illustrating the use of this procedure is given
in L-5.
(b) Stiffening rings shall extend completely around the
circumference of the cylinder except as permitted in (c)
below. Any joints between the ends or sections of such
rings, such as shown in Fig. UG-29.1(A) and (B), and any
connection between adjacent portions of a stiffening ring
lying inside or outside the shell as shown in Fig. UG29.1(C) shall be made so that the required moment of
inertia of the combined ring-shell section is maintained.
(c) Stiffening rings placed on the inside of a vessel may
be arranged as shown in Fig. UG-29.1(E) and (F) provided
that the required moment of inertia of the ring in (E) or
of the combined ring-shell section in (F) is maintained
within the sections indicated. Where the gap at (A) or (E)
does not exceed eight times the thickness of the shell plate,
the combined moment of inertia of the shell and stiffener
may be used.
Any gap in that portion of a stiffening ring supporting
the shell, such as shown in Fig. UG-29.1(D) and (E), shall
not exceed the length of arc given in Fig. UG-29.2 unless
additional reinforcement is provided as shown in Fig. UG29.1(C) or unless the following conditions are met:
(1) only one unsupported shell arc is permitted per
ring; and
(2) the length of the unsupported shell arc does not
exceed 90 deg; and
(3) the unsupported arcs in adjacent stiffening rings
are staggered 180 deg; and
(4) the dimension L defined in UG-28(b) is taken as
the larger of the following: the distance between alternate
stiffening rings, or the distance from the head tangent line
to the second stiffening ring plus one-third of the head
depth.
(d) When internal plane structures perpendicular to the
longitudinal axis of the cylinder (such as bubble trays or
baffle plates) are used in a vessel, they may also be considered to act as stiffening rings provided they are designed
to function as such.
(e) Any internal stays or supports used as stiffeners of
the shell shall bear against the shell of the vessel through
the medium of a substantially continuous ring.
(f) When closure bars or other rings are attached to both
the inner shell and outer jacket of a vessel, with pressure
in the space between the jacket and inner shell, this construction has adequate inherent stiffness, and therefore the
rules of this paragraph do not apply.
UG-30
ATTACHMENT OF STIFFENING
RINGS
(a) Stiffening rings may be placed on the inside or outside of a vessel, and except for the configurations permitted
by UG-29, shall be attached to the shell by welding or
brazing. Brazing may be used if the vessel is not to be
later stress relieved. The ring shall be essentially in contact
with the shell and meet the rules in UG-29(b) and (c).
Welding of stiffening rings shall comply with the requirements of this Division for the type of vessel under construction.
(b) Stiffening rings may be attached to the shell by
continuous, intermittent, or a combination of continuous
and intermittent welds or brazes. Some acceptable methods
of attaching stiffening rings are illustrated in Fig. UG-30.
(c) Intermittent welding shall be placed on both sides
of the stiffener and may be either staggered or in-line.
Length of individual fillet weld segments shall not be less
than 2 in. (50 mm) and shall have a maximum clear spacing
between toes of adjacent weld segments of 8t for external
rings and 12t for internal rings where t is the shell thickness
at the attachment. The total length of weld on each side
of the stiffening ring shall be:
(1) not less than one-half the outside circumference
of the vessel for rings on the outside; and
(2) not less than one-third the circumference of the
vessel for rings on the inside.
(d) A continuous full penetration weld is permitted as
shown in sketch (e) of Fig. UG-30. Continuous fillet welding or brazing on one side of the stiffener with intermittent
welding or brazing on the other side is permitted for
sketches (a), (b), (c), and (d) of Fig. UG-30 when the
thickness tw of the outstanding stiffening element [sketches
(a) and (c)] or width w of the stiffening element mating
to the shell [sketches (b) and (d)] is not more than 1 in.
(25 mm). The weld segments shall be not less than 2 in.
(50 mm) long and shall have a maximum clear spacing
between toes of adjacent weld segments of 24t.
(e) Strength of Attachment Welds. Stiffening ring attachment welds shall be sized to resist the full radial pressure
NOTE: Attention is called to the objection to supporting vessels through
the medium of legs or brackets, the arrangement of which may cause
concentrated loads to be imposed on the shell. Vertical vessels should
be supported through a substantial ring secured to the shell (see G-3).
Horizontal vessels, unless supported at or close to the ends (heads) or at
25
2010 SECTION VIII — DIVISION 1
FIG. UG-29.1 VARIOUS ARRANGEMENTS OF STIFFENING RINGS FOR CYLINDRICAL VESSELS SUBJECTED TO
EXTERNAL PRESSURE
26
2010 SECTION VIII — DIVISION 1
FIG. UG-29.2 MAXIMUM ARC OF SHELL LEFT UNSUPPORTED BECAUSE OF GAP IN STIFFENING RING OF
CYLINDRICAL SHELL UNDER EXTERNAL PRESSURE
load from the shell between stiffeners, and shear loads
acting radially across the stiffener caused by external
design loads carried by the stiffener (if any) and a computed
radial shear equal to 2% of the stiffening ring’s compressive load. See Example L-5 of Appendix L.
(1) The radial pressure load from shell, lb /in., is equal
to PLs.
(2) The radial shear load is equal to 0.01PLsDO.
(3) P, Ls, and DO are defined in UG-29.
(f) Minimum Size of Attachment Welds. The fillet weld
leg size shall be not less than the smallest of the following:
(1) 1⁄4 in. (6 mm);
(2) vessel thickness at the weld location;
(3) stiffener thickness at weld location.
UG-31
in accordance with the rules for shells in UG-27.
(b) External Pressure. The required wall thickness for
tubes and pipe under external pressure shall be determined
in accordance with the rules in UG-28.
(c) The thickness as determined under (a) or (b) above
shall be increased when necessary to meet the following
requirements:
(1) Additional wall thickness should be provided
when corrosion, erosion, or wear due to cleaning operations
is expected.
(2) Where ends are threaded, additional wall thickness is to be provided in the amount of 0.8 /n in. (20/n
mm) [where n equals the number of threads per inch (25.4
mm)].
TUBES, AND PIPE WHEN USED AS
TUBES OR SHELLS
NOTE: The requirements for rolling, expanding, or otherwise seating
tubes in tube plates may require additional wall thickness and careful
choice of materials because of possible relaxation due to differential
expansion stresses.
(a) Internal Pressure. The required wall thickness for
tubes and pipe under internal pressure shall be determined
27
2010 SECTION VIII — DIVISION 1
FIG. UG-30 SOME ACCEPTABLE METHODS OF ATTACHING STIFFENING RINGS
2 in. (50 mm)
min.
S
2 in. (50 mm)
min.
2 in. (50 mm)
min.
24t max.
S
tw
tw
w
In-line
Intermittent
Weld
Staggered
Intermittent
Weld
S
S
Continuous Fillet Weld
One Side, Intermittent
Other Side
8t external stiffeners
12t internal stiffeners
Stiffener
tw
tw
t
Shell
w
(a)
(b)
(c)
tw
Continuous full
penetration weld
t
w
(d)
(e)
28
2010 SECTION VIII — DIVISION 1
UG-32
(d) Ellipsoidal Heads With ts/L ≥ 0.002. The required
thickness of a dished head of semiellipsoidal form, in which
half the minor axis (inside depth of the head minus the
skirt) equals one-fourth of the inside diameter of the head
skirt, shall be determined by
FORMED HEADS, AND SECTIONS,
PRESSURE ON CONCAVE SIDE
(a) The minimum required thickness at the thinnest
point after forming18 of ellipsoidal, torispherical, hemispherical, conical, and toriconical heads under pressure on
the concave side (plus heads) shall be computed by the
appropriate formulas in this paragraph,19 except as permitted by Appendix 32. Heads with bolting flanges shall meet
the requirements of UG-35.1. In addition, provision shall
be made for any of the loadings listed in UG-22. The
provided thickness of the heads shall also meet the requirements of UG-16, except as permitted in Appendix 32.
(b) The thickness of an unstayed ellipsoidal or torispherical head shall in no case be less than the required thickness
of a seamless hemispherical head divided by the efficiency
of the head-to-shell joint.
(c) The symbols defined below are used in the formulas
of this paragraph:
tp
PD
2SEt
or P p
2SE − 0.2P
D + 0.2t
(1)
NOTE: For ellipsoidal heads with ts /L < 0.002, the rules of 1-4(f) shall
also be met.
An acceptable approximation of a 2:1 ellipsoidal head is
one with a knuckle radius of 0.17D and a spherical radius
of 0.90D.
(e) Torispherical Heads With ts/L ≥ 0.002. The required
thickness of a torispherical head for the case in which the
knuckle radius is 6% of the inside crown radius and the
inside crown radius equals the outside diameter of the skirt
[see UG-32(j)] shall be determined by
D p inside diameter of the head skirt; or inside length
of the major axis of an ellipsoidal head; or inside
diameter of a conical head at the point under
consideration, measured perpendicular to the longitudinal axis
Di p inside diameter of the conical portion of a toriconical head at its point of tangency to the knuckle,
measured perpendicular to the axis of the cone
p D − 2r (1 − cos )
E p lowest efficiency of any joint in the head; for
hemispherical heads this includes head-to-shell
joint; for welded vessels, use the efficiency specified in UW-12
L p inside spherical or crown radius. The value of L
for ellipsoidal heads shall be obtained from Table
UG-37.
P p internal design pressure (see UG-21)
r p inside knuckle radius
S p maximum allowable stress value in tension as
given in the tables referenced in UG-23, except
as limited in UG-24 and (e) below.
t p minimum required thickness of head after forming
ts p minimum specified thickness of head after forming, in. (mm). ts shall be ≥ t
p one-half of the included (apex) angle of the cone
at the centerline of the head (see Fig. 1-4)
tp
0.885PL
SEt
or P p
SE − 0.1P
0.885L + 0.1t
(2)
NOTE: For torispherical heads with ts /L < 0.002, the rules of 1-4(f)
shall also be met.
Torispherical heads made of materials having a specified
minimum tensile strength exceeding 70,000 psi (500 MPa)
shall be designed using a value of S equal to 20,000 psi
(150 MPa) at room temperature and reduced in proportion
to the reduction in maximum allowable stress values at
temperature for the material (see UG-23).
(f) Hemispherical Heads. When the thickness of a hemispherical head does not exceed 0.356L, or P does not
exceed 0.665SE, the following formulas shall apply:
tp
PL
2SEt
or P p
2SE − 0.2P
L + 0.2t
(3)
(g) Conical Heads and Sections (Without Transition
Knuckle). The required thickness of conical heads or conical shell sections that have a half apex-angle not greater
than 30 deg shall be determined by
tp
PD
2SEt cos or P p
2 cos (SE − 0.6P)
D + 1.2t cos (4)
A reinforcing ring shall be provided when required by the
rule in 1-5(d) and (e).
Conical heads or sections having a half apex-angle greater than 30 deg without a transition knuckle shall comply with Formula (4) and 1-5(g).
(h) Toriconical Heads and Sections. The required thickness of the conical portion of a toriconical head or section,
in which the knuckle radius is neither less than 6% of the
outside diameter of the head skirt nor less than three times
the knuckle thickness, shall be determined by Formula (4)
in (g) above, using Di in place of D.
18
In order to ensure that a finished head is not less than the minimum
thickness required, it is customary to use a thicker plate to take care of
possible thinning during the process of forming. The neck of an opening
in a head with an integrally flanged opening will thin out due to the
fluing operation. This is permissible provided the neck thickness is not
less than the thickness required for a cylindrical shell subject to internal
and /or external pressure, as applicable, and having an inside diameter
equal to the maximum diameter of the opening [see UG-38(a) and
UG-46(j)].
19
Formulas in terms of outside dimensions and for heads of other
proportions are given in 1-4 together with illustrative examples.
29
2010 SECTION VIII — DIVISION 1
TABLE UG-33.1
VALUES OF SPHERICAL RADIUS FACTOR Ko FOR
ELLIPSOIDAL HEAD WITH PRESSURE ON
CONVEX SIDE
Interpolation Permitted for Intermediate Values
The required thickness of the knuckle shall be determined by Formula (3) of 1-4(d) in which
Lp
Di
2 cos Toriconical heads or sections may be used when the
angle ≤ 30 deg and are mandatory for conical head
designs when the angle exceeds 30 deg, unless the design
complies with 1-5(g).
(i) When an ellipsoidal, torispherical, hemispherical,
conical, or toriconical head is of a lesser thickness than
required by the rules of this paragraph, it shall be stayed
as a flat surface according to the rules of UG-47 for braced
and stayed flat plates.
(j) The inside crown radius to which an unstayed head
is dished shall be not greater than the outside diameter
of the skirt of the head. The inside knuckle radius of a
torispherical head shall be not less than 6% of the outside
diameter of the skirt of the head but in no case less than
3 times the head thickness.
(k) A dished head with a reversed skirt may be used in a
pressure vessel provided the maximum allowable working
pressure for the head is established in accordance with the
requirements of UG-101.
(l) All formed heads, thicker than the shell and concave
to pressure, intended for butt welded attachment, shall have
a skirt length sufficient to meet the requirements of Fig.
UW-13.1, when a tapered transition is required. All formed
heads concave to pressure and intended for butt welded
attachment need not have an integral skirt when the thickness of the head is equal to or less than the thickness of
the shell. When a skirt is provided, its thickness shall be
at least that required for a seamless shell of the same inside
diameter.
(m) Heads concave to pressure, intended for attachment
by brazing, shall have a skirt length sufficient to meet the
requirements for circumferential joints in Part UB.
(n) Any taper at a welded joint within a formed head
shall be in accordance with UW-9. The taper at a circumferential welded joint connecting a formed head to a main
shell shall meet the requirements of UW-13 for the respective type of joint shown therein.
(o) If a torispherical, ellipsoidal, or hemispherical head
is formed with a flattened spot or surface, the diameter of
the flat spot shall not exceed that permitted for flat heads
as given by Formula (1) in UG-34, using C p 0.25.
(p) Openings in formed heads under internal pressure
shall comply with the requirements of UG-36 through
UG-46.
(q) A stayed jacket that completely covers a formed
inner head or any of the types included in this paragraph
shall also meet the requirements of UG-47(c).
Do / 2ho
Ko
...
...
3.0
1.36
2.8
1.27
2.6
1.18
2.4
1.08
2.2
0.99
Do / 2ho
Ko
2.0
0.90
1.8
0.81
1.6
0.73
1.4
0.65
1.2
0.57
1.0
0.50
UG-33
FORMED HEADS, PRESSURE ON
CONVEX SIDE
(a) General. The required thickness at the thinnest point
after forming [see footnote 18, UG-32(a)] of ellipsoidal,
torispherical, hemispherical, toriconical, and conical heads
and conical segments under pressure on the convex side
(minus heads) shall be computed by the appropriate formulas given in this paragraph (see UG-16). Heads with bolting
flanges shall meet the requirements of UG-35.1. In addition, provisions shall be made for any other loading given
in UG-22. The required thickness for heads due to pressure
on the convex side shall be determined as follows.
(1) For ellipsoidal and torispherical heads, the
required thickness shall be the greater of the following:
(a) the thickness computed by the procedure given
in UG-32 for heads with pressure on the concave side
(plus heads) using a design pressure 1.67 times the design
pressure on the convex side, assuming a joint efficiency
E p 1.00 for all cases; or
(b) the thickness as computed by the appropriate
procedure given in (d) or (e) below.
In determining the maximum allowable working pressure on the convex side of ellipsoidal or torispherical heads,
reverse the procedures in (a)(1)(a) and (a)(1)(b) above, and
use the smaller of the pressures obtained.
(2) For hemispherical heads, the required thickness
shall be determined by the rules given in (c) below.
(3) For conical and toriconical heads and conical sections, the required thickness shall be determined by the
rules given in (f) below.
(b) Nomenclature. The nomenclature defined below is
used in this paragraph. Figure 1-4 shows principal dimensions of typical heads.
A, B, E, and P are as defined in UG-28(b)
Do p outside diameter of the head skirt
Do / 2ho p ratio of the major to the minor axis of ellipsoidal heads, which equals the outside diameter
of the head skirt divided by twice the outside
height of the head (see Table UG-33.1)
DL p outside diameter at large end of conical section
under consideration
30
(10)
2010 SECTION VIII — DIVISION 1
Ds p outside diameter at small end of conical section
under consideration
Dss p outside diameter at small end of conical section
under consideration
ho p one-half of the length of the outside minor axis
of the ellipsoidal head, or the outside height of
the ellipsoidal head measured from the tangent
line (head-bend line)
Ko p factor depending on the ellipsoidal head proportions Do / 2ho (see Table UG-33.1)
Lc p axial length of cone or conical section (see
Fig. UG-33.1)
Le p equivalent length of conical head or section
between lines of support [see (UG-33(g)]
Ro p for hemispherical heads, the outside radius
p for ellipsoidal heads, the equivalent outside
spherical radius taken as Ko Do
p for torispherical heads, the outside radius of
the crown portion of the head
t p minimum required thickness of head after
forming, in. (mm)
te p effective thickness of conical section
p t cos p one-half the apex angle in conical heads and
sections, deg
convex side, either seamless or of built-up construction
with butt joints shall not be less than the minimum required
thickness of the adjacent cylindrical shell and, when a
knuckle is not provided, the reinforcement requirement of
1-8 shall be satisfied (see Fig. UG-28.1). When the cone-tocylinder junction is a line-of-support, the required thickness
shall be determined in accordance with the following subparagraphs.
(1) When is equal to or less than 60 deg:
(a) cones having DL /te values ≥ 10:
Step 1. Assume a value for te and determine the ratios
Le /DL and DL /te.
Step 2. Enter Fig. G of Subpart 3 of Section II, Part D
at a value of L /Do equivalent to the value of Le /DL determined in Step 1. For values of Le /DL greater than 50, enter
the chart at a value of Le /DL p 50.
Step 3. Move horizontally to the line for the value of
Do /t equivalent to the value of DL /te determined in Step
1. Interpolation may be made for intermediate values of
DL /te; extrapolation is not permitted. From this point of
intersection move vertically downwards to determine the
value of factor A.
Step 4. Using the value of A calculated in Step 3, enter
the applicable material chart in Subpart 3 of Section II,
Part D for the material under consideration. Move vertically
to an intersection with the material /temperature line for
the design temperature (see UG-20). Interpolation may be
made between lines for intermediate temperatures.
In cases where the value of A falls to the right of the
end of the material /temperature line, assume an intersection with the horizontal projection of the upper end of the
material /temperature line. For values of A falling to the
left of the material /temperature line, see Step 7.
Step 5. From the intersection obtained in Step 4, move
horizontally to the right and read the value of factor B.
Step 6. Using this value of B, calculate the value of the
maximum allowable external working pressure Pa using
the following formula:
(c) Hemispherical Heads. The required thickness of a
hemispherical head having pressure on the convex side
shall be determined in the same manner as outlined in
UG-28(d) for determining the thickness for a spherical
shell. An example illustrating the use of this procedure is
given in L-6.3.
(d) Ellipsoidal Heads. The required thickness of an
ellipsoidal head having pressure on the convex side, either
seamless or of built-up construction with butt joints, shall
not be less than that determined by the following procedure.
Step 1. Assume a value for t and calculate the value of
factor A using the following formula:
Ap
0.125
Ro / t
Pa p
Step 2. Using the value of A calculated in Step 1, follow
the same procedure as that given for spherical shells in
UG-28(d), Steps 2 through 6. An example illustrating the
use of this procedure is given in L-6.1.
(e) Torispherical Heads. The required thickness of a
torispherical head having pressure on the convex side,
either seamless or of built-up construction with butt joints,
shall not be less than that determined by the same design
procedure as is used for ellipsoidal heads given in (d)
above, using the appropriate value for Ro. An example
illustrating the use of this procedure is given in L-6.2.
(f) Conical Heads and Sections. When the cone-to-cylinder junction is not a line-of-support, the required thickness of a conical head or section under pressure on the
4B
3(DL / te )
Step 7. For values of A falling to the left of the applicable
material /temperature line, the value of Pa can be calculated
using the following formula:
Pa p
2AE
3(DL / te )
Step 8. Compare the calculated value of Pa obtained in
Steps 6 or 7 with P. If Pa is smaller than P, select a larger
value for t and repeat the design procedure until a value
of Pa is obtained that is equal to or greater than P. An
example illustrating the use of this procedure is given in
L-6.4.
Step 9. Provide adequate moment of inertia and reinforcement at the cone-to-cylinder junction in accordance
31
2010 SECTION VIII — DIVISION 1
(10)
FIG. UG-33.1 LENGTH Lc OF SOME TYPICAL CONICAL SECTIONS FOR EXTERNAL PRESSURE
32
2010 SECTION VIII — DIVISION 1
(2) When of the cone is greater than 60 deg, the
thickness of the cone shall be the same as the required
thickness for a flat head under external pressure, the diameter of which equals the largest diameter of the cone (see
UG-34).
(3) The thickness of an eccentric cone shall be taken
as the greater of the two thicknesses obtained using both
the smallest and largest in the calculations.
(g) The required thickness of a conical part of a toriconical head or conical section having pressure on the convex
side, either seamless or of built-up construction with butt
joints within the conical part of a toriconical head or conical
section, shall not be less than that determined from (f)
above with the exception that Le shall be determined as
follows:
(1) For illustrations (a) and (b) in Fig. UG-33.1,
with 1-8. For a junction with a knuckle, the reinforcement
calculation is not required, and the moment of inertia calculation may be performed either by considering the presence
of the knuckle or by assuming the knuckle is not present
whereby the cone is assumed to intersect the adjacent cylinder.
(b) cones having DL /te values <10:
Step 1. Using the same procedure as given in (f)(1)(a)
above, obtain the value of B. For values of DL /te less than 4,
the value of factor A can be calculated using the following
formula:
Ap
1.1
(DL / te ) 2
For values of A greater than 0.10, use a value of 0.10.
Step 2. Using the value of B obtained in Step 1, calculate
a value Pa1 using the following formula:
Pa1 p
Le p 共Lc / 2兲共1 + Ds / DL兲
冤(D / t ) − 0.0833冥 B
2.167
L
(2) For sketch (c) in Fig. UG-33.1,
e
Le p r1 sin +
Step 3. Calculate a value P a2 using the following
formula:
冢
L c DL + D s
2
DLs
冣
(3) For sketch (d) in Fig. UG-33.1,
Pa2
冤
2S
1
p
1−
DL / t e
DL / t e
冥
Le p r 2
where
冢
L D + Ds
Dss
sin + c L
DL
2
DL
冣
(4) For sketch (e) in Fig. UG-33.1,
S p the lesser of two times the maximum allowable
stress value in tension at design metal temperature, from the applicable table referenced by
UG-23, or 0.9 times the yield strength of the material at design temperature
冢
L e p r1 + r 2
冣
L (D + Ds )
Dss
sin + c L
DL s
2
DLs
(h) When lap joints are used in formed head construction or for longitudinal joints in a conical head under external pressure, the thickness shall be determined by the rules
in this paragraph, except that 2P shall be used instead of
P in the calculations for the required thickness.
(i) The required length of skirt on heads convex to pressure shall comply with the provisions of UG-32(l) and (m)
for heads concave to pressure.
(j) Openings in heads convex to pressure shall comply
with the requirements of UG-36 through UG-46.
Values of yield strength are obtained from the applicable
external pressure chart as follows.
(a) For a given temperature curve, determine the
B value that corresponds to the right hand side termination
point of the curve.
(b) The yield strength is twice the B value
obtained in (a) above.
Step 4. The smaller of the values of Pa1 calculated in
Step 2, or Pa2 calculated in Step 3 shall be used for the
maximum allowable external working pressure Pa. Compare Pa with P. If Pa is smaller than P, select a larger value
for t and repeat the design procedure until a value for Pa
is obtained that is equal to or greater than P.
Step 5. Provide adequate moment of inertia and reinforcement at the cone-to-cylinder junction in accordance
with 1-8. For a junction with a knuckle, the reinforcement
calculation is not required, and the moment of inertia calculation may be performed either by considering the presence
of the knuckle or by assuming the knuckle is not present
whereby the cone is assumed to intersect the adjacent cylinder.
UG-34
UNSTAYED FLAT HEADS AND
COVERS
(a) The minimum thickness of unstayed flat heads,
cover plates and blind flanges shall conform to the requirements given in this paragraph. These requirements apply
to both circular and noncircular20 heads and covers. Some
acceptable types of flat heads and covers are shown in
20
Special consideration shall be given to the design of shells, nozzle
necks or flanges to which noncircular heads or covers are attached [see
U-2(g)].
33
2010 SECTION VIII — DIVISION 1
(c) The thickness of flat unstayed heads, covers, and
blind flanges shall conform to one of the following three
requirements.21
(1) Circular blind flanges conforming to any of the
flange standards listed in Table U-3 and further limited in
UG-44 shall be acceptable for the diameters and pressure–
temperature ratings in the respective standard when the
blind flange is of the types shown in Fig. UG-34 sketches
(j) and (k).
(2) The minimum required thickness of flat unstayed
circular heads, covers and blind flanges shall be calculated
by the following formula:
Fig. UG-34. In this figure, the dimensions of the component
parts and the dimensions of the welds are exclusive of
extra metal required for corrosion allowance.
(b) The symbols used in this paragraph and in
Fig. UG-34 are defined as follows:
C p a factor depending upon the method of attachment
of head, shell dimensions, and other items as listed
in (d) below, dimensionless. The factors for
welded covers also include a factor of 0.667 that
effectively increases the allowable stress for such
constructions to 1.5S.
D p long span of noncircular heads or covers measured
perpendicular to short span
d p diameter, or short span, measured as indicated in
Fig. UG-34
E p joint efficiency, from Table UW-12, of any Category A weld as defined in UW-3(a)
hG p gasket moment arm, equal to the radial distance
from the centerline of the bolts to the line of the
gasket reaction, as shown in Table 2-5.2
L p perimeter of noncircular bolted head measured
along the centers of the bolt holes
m p the ratio tr /ts, dimensionless
P p internal design pressure (see UG-21)
r p inside corner radius on a head formed by flanging
or forging
S p maximum allowable stress value in tension from
applicable table of stress values referenced by
UG-23
t p minimum required thickness of flat head or cover
tf p nominal thickness of the flange on a forged head,
at the large end, as indicated in Fig. UG-34
sketch (b)
th p nominal thickness of flat head or cover
tr p required thickness of seamless shell, for pressure
ts p nominal thickness of shell
tw p thickness through the weld joining the edge of a
head to the inside of a vessel, as indicated in Fig.
UG-34 sketch (g)
t1 p throat dimension of the closure weld, as indicated
in Fig. UG-34 sketch (r)
W p total bolt load given for circular heads for Formulas (3) and (4), 2-5(e)
Y p length of flange of flanged heads, measured from
the tangent line of knuckle, as indicated in Fig.
UG-34 sketches (a) and (c), in. (mm)
Z p a factor of noncircular heads and covers that
depends on the ratio of short span to long span,
as given in (c) below, dimensionless
t p d 冪 CP / SE
(1)
except when the head, cover, or blind flange is attached
by bolts causing an edge moment [sketches (j) and (k)] in
which case the thickness shall be calculated by
t p d 冪CP / SE + 1.9WhG / SEd 3
(2)
When using Formula (2), the thickness t shall be calculated
for both operating conditions and gasket seating, and the
greater of the two values shall be used. For operating
conditions, the value of P shall be the design pressure, and
the values of S at the design temperature and W from
Formula (3) of 2-5(e) shall be used. For gasket seating, P
equals zero, and the values of S at atmospheric temperature
and W from Formula (4) of 2-5(e) shall be used.
(3) Flat unstayed heads, covers, or blind flanges may
be square, rectangular, elliptical, obround, segmental, or
otherwise noncircular. Their required thickness shall be
calculated by the following formula:
t p d 冪 ZCP / SE
(3)
2.4d
D
(4)
where
Z p 3.4 −
with the limitation that Z need not be greater than two and
one-half (2.5).
Formula (3) does not apply to noncircular heads, covers,
or blind flanges attached by bolts causing a bolt edge
moment [sketches (j) and (k)]. For noncircular heads of
this type, the required thickness shall be calculated by the
following formula:
t p d 冪 ZCP / SE + 6WhG / SELd 2
(5)
When using Formula (5), the thickness t shall be calculated
in the same way as specified above for Formula (2).
21
The formulas provide safe construction as far as stress is concerned.
Greater thicknesses may be necessary if deflection would cause leakage
at threaded or gasketed joints.
34
2010 SECTION VIII — DIVISION 1
FIG. UG-34 SOME ACCEPTABLE TYPES OF UNSTAYED FLAT HEADS AND COVERS
Center of weld
Y
t
ts
Taper
Tangent ts
line
r = 3t
min.
t
d
C = 0.17 or
C = 0.10
(a)
Center of lap
ts
tf min. = 2ts
t
rmin. = 0.375 in. (10 mm) s
for ts 11/2 in. (38 mm)
rmin. = 0.25ts for
ts 11/2 in. (38 mm)
but need not be greater
than 3/4 in. (19 mm)
tf
r = 3tf
min.
t
d
d
t
C = 0.33m
C min. = 0.20
(b-2)
C = 0.17
(b-1)
Y
t
Tangent
line
r = 3t
min.
t
d
C = 0.30
C = 0.20 or 0.13
(c)
tw = 2tr min. nor less than 1.2ts
but need not be greater than t
t
0.7ts
0.7ts
0.7ts
d
ts
t
C = 0.13
0.7ts
d
ts
Bevel is optional
Continuation
t of shell
optional
d
t
Projection
beyond weld
is optional
ts
r = 1/4t
min.
d
t
45 deg max.
Sketches (e), (f), and (g) circular covers, C = 0.33m, Cmin. = 0.20
(e)
(d)
(f)
See Fig. UW-13.2 sketches (a) to (g),
inclusive, for details of welded joint
ts not less than 1.25tr
ts
See Fig. UW-13.2 sketches (a) to (g),
inclusive, for details of outside
welded joint
0.7ts
ts
d
Retaining
ring
d
d
t
Threaded ring
d
t
C = 0.30
(n)
C = 0.30
(o)
t1
ts
30 deg min.
45 deg max.
t
d
d
C = 0.25
(p)
C = 0.3
[Use Eq. (2) or (5)]
(k)
t
C = 0.30
(m)
t
t
C = 0.3
[Use Eq. (2) or (5)]
(j)
d
t
d
t
C = 0.33m
C min. = 0.20
(i)
(h)
hG
hG
d
t
C = 0.33
(g)
d
min. t1 = t or ts
whichever
is greater
C = 0.33
(r)
t
When pipe threads are
used, see Table UG-43
C = 0.75
(q)
Seal weld
3/ t min.
4
t
0.8ts min.
or
d
C = 0.33
(s)
GENERAL NOTE: The above illustrations are diagrammatic only. Other designs that meet the requirements of UG-34 are acceptable.
35
2010 SECTION VIII — DIVISION 1
(d) For the types of construction shown in Fig. UG-34,
the minimum values of C to be used in Formulas (1), (2),
(3), and (5) are:
Sketch (a). C p 0.17 for flanged circular and noncircular
heads forged integral with or butt welded to the vessel
with an inside corner radius not less than three times the
required head thickness, with no special requirement with
regard to length of flange, and where the welding meets
all the requirements for circumferential joints given in
Part UW.
C p 0.10 for circular heads, when the flange length for
heads of the above design is not less than
冢
Y p 1.1 − 0.8
ts2
th2
冣 冪dt
least four, and the threaded parts are at least as strong as
the threads for standard piping of the same diameter. Seal
welding may be used, if desired.
Sketch (d). C p 0.13 for integral flat circular heads
when the dimension d does not exceed 24 in. (600 mm),
the ratio of thickness of the head to the dimension d is not
less than 0.05 or greater than 0.25, the head thickness th
is not less than the shell thickness ts , the inside corner
radius is not less than 0.25t, and the construction is obtained
by special techniques of upsetting and spinning the end of
the shell, such as employed in closing header ends.
Sketches (e), (f), and (g). C p 0.33m but not less than
0.20 for circular plates, welded to the inside of a vessel,
and otherwise meeting the requirements for the respective
types of welded vessels. If a value of m less than 1 is used
in calculating t, the shell thickness ts shall be maintained
along a distance inwardly from the inside face of the head
(6)
h
C p 0.10 for circular heads, when the flange length Y
is less than the requirements in Formula (6) but the shell
thickness is not less than
ts p 1.12th
冪1.1 − Y / 冪dt
h
equal to at least 2冪dts. The throat thickness of the fillet
welds in sketches (e) and (f) shall be at least 0.7ts. The
size of the weld tw in sketch (g) shall be not less than 2
times the required thickness of a seamless shell nor less
than 1.25 times the nominal shell thickness but need not
be greater than the head thickness; the weld shall be deposited in a welding groove with the root of the weld at the
inner face of the head as shown in the sketch.
C p 0.33 for noncircular plates, welded to the inside
of a vessel and otherwise meeting the requirements for the
respective types of welded vessels. The throat thickness
of the fillet welds in sketches (e) and (f) shall be at least
0.7ts. The size of the weld tw in sketch (g) shall be not less
than 2 times the required thickness of a seamless shell nor
less than 1.25 times the nominal shell thickness but need
not be greater than the head thickness; the weld shall be
deposited in a welding groove with the root of the weld
at the inner face of the head as shown in the sketch.
Sketch (h). C p 0.33 for circular plates welded to the
end of the shell when ts is at least 1.25tr and the weld
details conform to the requirements of UW-13(e) and Fig.
UW-13.2 sketches (a) to (g) inclusive. See also
UG-93(d)(3).
Sketch (i). C p 0.33m but not less than 0.20 for circular
plates if an inside fillet weld with minimum throat thickness
of 0.7ts is used and the details of the outside weld conform
to the requirements of UW-13(e) and Fig. UW-13.2
sketches (a) to (g) inclusive, in which the inside weld can
be considered to contribute an amount equal to ts to the
sum of the dimensions a and b. See also UG-93(d)(3).
Sketches (j) and (k). C p 0.3 for circular and noncircular
heads and covers bolted to the vessel as indicated in the
figures. Note that Formula (2) or (5) shall be used because
of the extra moment applied to the cover by the bolting.
When the cover plate is grooved for a peripheral gasket,
as shown in sketch (k), the net cover plate thickness under
(7)
for a length of at least 2冪dts.
When C p 0.10 is used, the taper shall be at least 1:3.
Sketch (b-1). C p 0.17 for forged circular and noncircular heads integral with or butt welded to the vessel, where
the flange thickness is not less than two times the shell
thickness, the corner radius on the inside is not less than
three times the flange thickness, and the welding meets
all the requirements for circumferential joints given in
Part UW.
Sketch (b-2). C p 0.33m but not less than 0.20 for
forged circular and noncircular heads integral with or butt
welded to the vessel, where the flange thickness is not less
than the shell thickness, the corner radius on the inside is
not less than the following:
rmin p 0.375 in. (10 mm) for ts ≤ 11/2 in. (38 mm)
rmin p 0.25ts for ts > 11/ in. (38 mm) but need not be
greater than 3/4 in. (19 mm)
The welding shall meet all the requirements for circumferential joints given in Part UW.
Sketch (c). C p 0.13 for circular heads lap welded or
brazed to the shell with corner radius not less than 3t and
Y not less than required by Formula (6) and the requirements of UW-13 are met.
C p 0.20 for circular and noncircular lap welded or
brazed construction as above, but with no special requirement with regard to Y.
C p 0.30 for circular flanged plates screwed over the
end of the vessel, with inside corner radius not less than
3t, in which the design of the threaded joint against failure
by shear, tension, or compression, resulting from the end
force due to pressure, is based on a factor of safety of at
36
2010 SECTION VIII — DIVISION 1
the groove or between the groove and the outer edge of
the cover plate shall be not less than
d 冪1.9WhG / Sd
3
UG-35
OTHER TYPES OF CLOSURES
UG-35.1
Dished Covers
Requirements for design of dished heads with bolting
flanges are given in 1-6.
for circular heads and covers, nor less than
d 冪 6WhG / SLd 2
UG-35.2
for noncircular heads and covers.
Sketches (m), (n), and (o). C p 0.3 for a circular plate
inserted into the end of a vessel and held in place by a
positive mechanical locking arrangement, and when all
possible means of failure (either by shear, tension, compression, or radial deformation, including flaring, resulting
from pressure and differential thermal expansion) are
resisted with a factor of safety of at least four. Seal welding
may be used, if desired.
Sketch (p). C p 0.25 for circular and noncircular covers
bolted with a full-face gasket, to shells, flanges or side
plates.
Sketch (q). C p 0.75 for circular plates screwed into
the end of a vessel having an inside diameter d not
exceeding 12 in. (300 mm); or for heads having an integral
flange screwed over the end of a vessel having an inside
diameter d not exceeding 12 in. (300 mm); and when the
design of the threaded joint, against failure by shear, tension, compression, or radial deformation, including flaring,
resulting from pressure and differential thermal expansion,
is based on a factor of safety of at least four. If a tapered
pipe thread is used, the requirements of Table UG-43 shall
also be met. Seal welding may be used, if desired.
Sketch (r). C p 0.33 for circular plates having a dimension d not exceeding 18 in. (450 mm) inserted into the
vessel as shown and otherwise meeting the requirements
for the respective types of welded vessels. The end of the
vessel shall be crimped over at least 30 deg, but not more
than 45 deg. The crimping may be done cold only when
this operation will not injure the metal. The throat of the
weld shall be not less than the thickness of the flat head
or shell, whichever is greater.
Sketch (s). C p 0.33 for circular beveled plates having
a diameter d not exceeding 18 in. (450 mm), inserted into
a vessel, the end of which is crimped over at least 30 deg,
but not more than 45 deg, and when the undercutting for
seating leaves at least 80% of the shell thickness. The
beveling shall be not less than 75% of the head thickness.
The crimping shall be done when the entire circumference
of the cylinder is uniformly heated to the proper forging
temperature for the material used. For this construction,
the ratio ts /d shall be not less than the ratio P /S nor less
than 0.05. The maximum allowable pressure for this construction shall not exceed P p S /5d for Customary units
(P p 127S /d for SI units).
This construction is not permissible if machined from
rolled plate.
Quick-Actuating (Quick-Opening)
Closures
UG-35.2(a) Definitions
UG-35.2(a)(1) Quick-actuating or quick-opening
closures are those that permit substantially faster access to
the contents space of a pressure vessel than would be
expected with a standard bolted flange connection (bolting
through one or both flanges). Closures with swing bolts
are not considered quick-actuating (quick-opening).
UG-35.2(a)(2) Holding elements are parts of the closure used to hold the cover to the vessel, and/or to provide
the load required to seal the closure. Hinge pins or bolts
can be holding elements.
UG-35.2(a)(3) Locking components are parts of the
closure that prevent a reduction in the load on a holding
element that provides the force required to seal the closure,
or prevent the release of a holding element. Locking components may also be used as holding elements.
UG-35.2(a)(4) The locking mechanism or locking
device may consist of a combination of locking components.
UG-35.2(a)(5) The use of a multi-link component,
such as a chain, as a holding element is not permitted.
UG-35.2(b) General Design Requirements
UG-35.2(b)(1) Quick-actuating closures shall be
designed such that the locking elements will be engaged
prior to or upon application of pressure and will not disengage until the pressure is released.
UG-35.2(b)(2) Quick-actuating closures shall be
designed such that the failure of a single locking component
while the vessel is pressurized (or contains a static head
of liquid acting at the closure) will not:
(a) cause or allow the closure to be opened or
leak; or
(b) result in the failure of any other locking component or holding element; or
(c) increase the stress in any other locking component or holding element by more than 50% above the
allowable stress of the component.
UG-35.2(b)(3) Quick-actuating closures shall be
designed and installed such that it may be determined by
visual external observation that the holding elements are
in satisfactory condition.
UG-35.2(b)(4) Quick-actuating closures shall also be
designed so that all locking components can be verified to
be fully engaged by visual observation or other means
prior to the application of pressure to the vessel.
37
2010 SECTION VIII — DIVISION 1
UG-35.2(b)(5) When installed, all vessels having
quick-actuating closures shall be provided with a pressure
indicating device visible from the operating area and suitable to detect pressure at the closure.
UG-35.2(c) Specific Design Requirements
UG-35.2(c)(1) Quick-actuating closures that are held
in position by positive locking devices and that are fully
released by partial rotation or limited movement of the
closure itself or the locking mechanism, and any closure
that is other than manually operated, shall be so designed
that when the vessel is installed the following conditions
are met:
(a) The closure and its holding elements are fully
engaged in their intended operating position before pressure can be applied in the vessel.
(b) Pressure tending to force the closure open or
discharge the vessel contents clear of the vessel shall be
released before the closure can be fully opened for access.
(c) In the event that compliance with UG-35.2
(c)(1)(a) and (c)(1)(b) above is not inherent in the design
of the closure and its holding elements, provisions shall
be made so that devices to accomplish this can be added
when the vessel is installed.
UG-35.2(c)(2) The design rules of Appendix 2 of this
Division may not be applicable to design quick-actuating
or quick-opening closures; see 2-1(e).
UG-35.2(c)(3) The designer shall consider the effects
of cyclic loading, other loadings (see UG-22) and mechanical wear on the holding and locking components.
UG-35.2(c)(4) It is recognized that it is impractical
to write requirements to cover the multiplicity of devices
used for quick access, or to prevent negligent operation or
the circumventing of safety devices. Any device or devices
that will provide the safeguards broadly described in UG35.2(c)(1)(a), (c)(1)(b), and (c)(1)(c) above will meet the
intent of this Division.
UG-35.2(d) Alternative Designs for Manually Operated
Closures
UG-35.2(d)(1) Quick-actuating closures that are held
in position by a locking mechanism designed for manual
operation shall be designed such that if an attempt is made
to open the closure when the vessel is under pressure, the
closure will leak prior to full disengagement of the locking
components and release of the closure. The design of the
closure and vessel shall be such that any leakage shall be
directed away from the normal position of the operator.
UG-35.2(d)(2) Manually operated closures need not
satisfy UG-35.2 (c)(1)(a), (c)(1)(b), or (c)(1)(c) above, but
such closures shall be equipped with an audible or visible
warning device that will warn the operator if pressure is
applied to the vessel before the holding elements and locking components are fully engaged in their intended position
or if an attempt is made to disengage the locking mechanism before the pressure within the vessel is released.
UG-35.2(e) Supplementary Requirements for QuickActuation (Quick-Opening) Closures
Nonmandatory Appendix FF provides additional design
information for the Manufacturer and provides installation,
operational, and maintenance requirements for the Owner.
OPENINGS AND REINFORCEMENTS22
(Typical examples of the application of these rules are
given in Appendix L.)
UG-36
OPENINGS IN PRESSURE VESSELS
(a) Shape of Opening23
(1) Openings in cylindrical or conical portions of vessels, or in formed heads, shall preferably be circular, elliptical, or obround. 24 When the long dimension of an
elliptical or obround opening exceeds twice the short
dimensions, the reinforcement across the short dimensions
shall be increased as necessary to provide against excessive
distortion due to twisting moment.
(2) Openings may be of other shapes than those given
in (1) above, and all corners shall be provided with a
suitable radius. When the openings are of such proportions
that their strength cannot be computed with assurance of
accuracy, or when doubt exists as to the safety of a vessel
with such openings, the part of the vessel affected shall
be subjected to a proof hydrostatic test as prescribed in
UG-101.
(b) Size of Openings
(1) Properly reinforced openings in cylindrical and
conical shells are not limited as to size except with the
following provisions for design. The rules in UG-36
through UG-43 apply to openings not exceeding the following: for vessels 60 in. (1 500 mm) inside diameter and
less, one-half the vessel diameter, but not to exceed 20
in. (500 mm); for vessels over 60 in. (1 500 mm) inside
diameter, one-third the vessel diameter, but not to exceed
40 in. (1 000 mm). (For conical shells, the inside shell
diameter as used above is the cone diameter at the center
of the opening.) For openings exceeding these limits, supplemental rules of 1-7 shall be satisfied in addition to the
22
The rules governing openings as given in this Division are based
on the stress intensification created by the existence of a hole in an
otherwise symmetrical section. External loadings such as those due to
the thermal expansion or unsupported weight of connecting piping have
not been evaluated. These factors should be given attention in unusual
designs or under conditions of cyclic loading.
23
The opening made by a pipe or a circular nozzle, the axis of which
is not perpendicular to the vessel wall or head, may be considered an
elliptical opening for design purposes.
24
An obround opening is one which is formed by two parallel sides
and semicircular ends.
38
(10)
2010 SECTION VIII — DIVISION 1
FIG. UG-36 LARGE HEAD OPENINGS — REVERSE-CURVE AND CONICAL SHELL-REDUCER SECTIONS
rules of this paragraph. Alternatively, openings in cylindrical or conical shells exceeding these limits may be designed
for internal pressure using the rules of 1-10. [See UG36(c)(2)(d).]
(2) Properly reinforced openings in formed heads and
spherical shells are not limited in size. For an opening in
an end closure, which is larger than one-half the inside
diameter of the shell, one of the following alternatives to
reinforcement may also be used:
(a) a conical section as shown in Fig. UG-36
sketch (a);
(b) a cone with a knuckle radius at the large end
as shown in Fig. UG-36 sketch (b);
(c) a reverse curve section as shown in Fig. UG36 sketches (c) and (d); or
(d) using a flare radius at the small end as shown
in Fig. UG-33.1 sketch (d).
The design shall comply with all the requirements of
the rules for reducer sections [see (e) below] insofar as
these rules are applicable.
(c) Strength and Design of Finished Openings
(1) All references to dimensions in this and succeeding paragraphs apply to the finished construction after
deduction has been made for material added as corrosion
allowance. For design purposes, no metal added as corrosion allowance may be considered as reinforcement. The
finished opening diameter is the diameter d as defined in
UG-37 and in Fig. UG-40.
(2)(a) Openings in cylindrical or conical shells, or
formed heads shall be reinforced to satisfy the requirements
in UG-37 except as given in (c), (d), and (3) below.
(b) Openings in flat heads shall be reinforced as
required by UG-39.
39
2010 SECTION VIII — DIVISION 1
(c) Openings in cylindrical and conical shells subjected to internal pressure may be designed to satisfy the
requirements in Mandatory Appendix 1, section 1-9 in lieu
of the internal pressure requirements in UG-37.
(d) Openings in cylindrical and conical shells subjected to internal pressure may be designed to satisfy the
requirements in Mandatory Appendix 1, 1-10 in lieu of
the internal pressure requirements in UG-37.
(3) Openings in vessels not subject to rapid fluctuations in pressure do not require reinforcement other than
that inherent in the construction under the following conditions:
(a) welded, brazed, and flued connections meeting
the applicable rules and with a finished opening not
larger than:
by other elements, e.g., inner shells, stays, or tubes, the
rules of this paragraph do not apply.
(2) The thickness of each element of a reducer, as
defined in (4) below, under internal pressure shall not
be less than that computed by the applicable formula. In
addition, provisions shall be made for any of the other
loadings listed in UG-22, where such loadings are
expected.
(3) The symbols defined in either UG-32(c) or below
are used in this paragraph (see Fig. UG-36).
t p minimum required thickness of the considered
element of a reducer after forming
RL p inside radius of larger cylinder
rL p inside radius of knuckle at larger cylinder
Rs p inside radius of smaller cylinder
rs p radius to the inside surface of flare at the small end
p one-half of the included (apex) angle of a conical
element
31⁄2 in. (89 mm) diameter — in vessel shells or heads with
a required minimum thickness of 3⁄8 in. (10 mm) or less;
3
2 ⁄8 in. (60 mm) diameter — in vessel shells or heads over
a required minimum thickness of 3⁄8 in. (10 mm);
(4) Elements of a Reducer. A transition section
reducer consisting of one or more elements may be used
to join two cylindrical shell sections of different diameters
but with a common axis provided the requirements of this
paragraph are met.
(a) Conical Shell Section. The required thickness
of a conical shell section, or the allowable working pressure
for such a section of given thickness, shall be determined
by the formulas given in UG-32(g).
(b) Knuckle Tangent to the Larger Cylinder.
Where a knuckle is used at the large end of a reducer
section, its shape shall be that of a portion of an ellipsoidal,
hemispherical, or torispherical head. The thickness and
other dimensions shall satisfy the requirements of the
appropriate formulas and provisions of UG-32.
(5) Combination of Elements to Form a Reducer.
When elements of (4) above, having different thicknesses
are combined to form a reducer, the joints including the
plate taper required by UW-9(c) shall lie entirely within
the limits of the thinner element being joined.
(a) A reducer may be a simple conical shell section,
Fig. UG-36 sketch (a), without knuckle, provided the halfapex angle is not greater than 30 deg, except as provided
for in 1-5(g). A reinforcement ring shall be provided at
either or both ends of the reducer when required by the
rules of 1-5.
(b) A toriconical reducer, Fig. UG-36 sketch (b),
may be shaped as a portion of a toriconical head, UG-32(h),
a portion of a hemispherical head plus a conical section,
or a portion of an ellipsoidal head plus a conical section,
provided the half-apex angle is not greater than 30 deg,
except as provided for in 1-5(g). A reinforcement ring shall
be provided at the small end of the conical reducer element
when required by the rules in 1-5.
(b) threaded, studded, or expanded connections in
which the hole cut in the shell or head is not greater than
23⁄8 in. (60 mm) diameter;
(c) no two isolated unreinforced openings, in
accordance with (a) or (b) above, shall have their centers
closer to each other than the sum of their diameters;
(d) no two unreinforced openings, in a cluster of
three or more unreinforced openings in accordance with
(a) or (b) above, shall have their centers closer to each
other than the following: for cylindrical or conical shells,
(1 + 1.5 cos )(d1 + d2);
for doubly curved shells and formed or flat heads,
2.5(d1 + d2)
where
p the angle between the line connecting the center of the openings and the longitudinal axis
of the shell
d1,d2 p the finished diameter of the two adjacent
openings
The centerline of an unreinforced opening as defined in
(a) and (b) above shall not be closer than its finished
diameter to any material used for reinforcement of an adjacent reinforced opening.
(d) Openings Through Welded Joints. Additional provisions governing openings through welded joints are given
in UW-14.
(e) Reducer Sections Under Internal Pressure
(1) The formulas and rules of this paragraph apply
to concentric reducer sections wherein all the longitudinal
loads are transmitted wholly through the shell of the
reducer. Where loads are transmitted in part or as a whole
40
2010 SECTION VIII — DIVISION 1
FIG. UG-37 CHART FOR DETERMINING VALUE OF F,
AS REQUIRED IN UG-37
(c) Reverse curve reducers, Fig. UG-36 sketches
(c) and (d), may be shaped of elements other than those
of (e)(4) above. See U-2(g).
(f) Reducers Under External Pressure. The rules of
UG-33(f) shall be followed, where applicable, in the design
of reducers under external pressure.
(g) Oblique Conical Shell Sections Under Internal Pressure. A transition section reducer consisting of an oblique
conical shell section may be used to join two cylindrical
shell sections of different diameters and axes, provided the
following requirements are used:
(1) The required thickness shall be determined by the
formulas given in UG-32(g).
(2) The angle to be used shall be the largest
included angle between the oblique cone and the attached
cylindrical section [see Fig. UG-36 sketch (e)] and shall
not be greater than 30 deg.
(3) Diametrical dimensions to be used in the design
formulas shall be measured perpendicular to the axis of
the cylinder to which the cone is attached.
(4) A reinforcement ring shall be provided at either
or both ends of the reducer when required by the rules of
1-5.
UG-37
REINFORCEMENT REQUIRED FOR
OPENINGS IN SHELLS AND
FORMED HEADS
(a) Nomenclature. The symbols used in this paragraph
are defined as follows:
A p total cross-sectional area of reinforcement
required in the plane under consideration (see Fig.
UG-37.1) (includes consideration of nozzle area
through shell if Sn /Sv<1.0)
A1 p area in excess thickness in the vessel wall available for reinforcement (see Fig. UG-37.1)
(includes consideration of nozzle area through
shell if Sn /Sv<1.0)
A2 p area in excess thickness in the nozzle wall available for reinforcement (see Fig. UG-37.1)
A3 p area available for reinforcement when the nozzle
extends inside the vessel wall (see Fig. UG-37.1)
A5 p cross-sectional area of material added as reinforcement (see Fig. UG-37.1)
A41, A42,
A43 p cross-sectional area of various welds available for
reinforcement (see Fig. UG-37.1)
c p corrosion allowance
D p inside shell diameter
Dp p outside diameter of reinforcing element (actual
size of reinforcing element may exceed the limits
of reinforcement established by UG-40; however,
credit cannot be taken for any material outside
these limits)
d p finished diameter of circular opening or finished
dimension (chord length at midsurface of thickness excluding excess thickness available for reinforcement) of nonradial opening in the plane
under consideration, in. (mm) [see Figs. UG-37.1
and UG-40]
E p 1 (see definitions for tr and tr n)
E1 p 1 when an opening is in the solid plate or in a
Category B butt joint; or
p 0.85 when an opening is located in an ERW or
autogenously welded pipe or tube. If the ERW or
autogenously welded joint is clearly identifiable
and it can be shown that the opening does not pass
through this weld joint, then E1 may be determined
using the other rules of this paragraph; or
p joint efficiency obtained from Table UW-12 when
any part of the opening passes through any other
welded joint
41
2010 SECTION VIII — DIVISION 1
FIG. UG-37.1 NOMENCLATURE AND FORMULAS FOR REINFORCED OPENINGS
GENERAL NOTE: This figure illustrates a common nozzle configuration and is not intended to prohibit other configurations permitted by the Code.
NOTE:
(1) This formula is applicable for a rectangular cross-sectional element that falls within the limits of reinforcement.
42
2010 SECTION VIII — DIVISION 1
t p specified vessel wall thickness,25 (not including
forming allowances). For pipe it is the nominal
thickness less manufacturing undertolerance
allowed in the pipe specification.
te p thickness or height of reinforcing element(see Fig.
UG-40)
ti p nominal thickness of internal projection of nozzle wall
tn p nozzle wall thickness.25 Except for pipe, this is the
wall thickness not including forming allowances.
For pipe, use the nominal thickness [see
UG-16(d)].
tr p required thickness of a seamless shell based on
the circumferential stress, or of a formed head,
computed by the rules of this Division for the
designated pressure, using E p 1, except that:
(a) when the opening and its reinforcement
are entirely within the spherical portion of a torispherical head, tr is the thickness required by 14(d), using M p 1;
(b) when the opening is in a cone, tr is the
thickness required for a seamless cone of diameter
D measured where the nozzle axis pierces the
inside wall of the cone;
(c) when the opening and its reinforcement
are in an ellipsoidal head and are located entirely
within a circle the center of which coincides with
the center of the head and the diameter of which
is equal to 80% of the shell diameter, tr is the
thickness required for a seamless sphere of radius
K1D, where D is the shell diameter and K1 is given
by Table UG-37.
tr n p required thickness of a seamless nozzle wall
W p total load to be carried by attachment welds (see
UG-41)
TABLE UG-37
VALUES OF SPHERICAL RADIUS FACTOR K1
D/2h
K1
...
...
3.0
1.36
2.8
1.27
2.6
1.18
2.4
1.08
2.2
0.99
D/2h
K1
2.0
0.90
1.8
0.81
1.6
0.73
1.4
0.65
1.2
0.57
1.0
0.50
GENERAL NOTES:
(a) Equivalent spherical radius p K1D;D/2h p axis ratio.
(b) For definitions, see 1-4(b).
(c) Interpolation permitted for intermediate values.
F p correction factor that compensates for the variation in internal pressure stresses on different
planes with respect to the axis of a vessel. A value
of 1.00 shall be used for all configurations except
that Fig. UG-37 may be used for integrally reinforced openings in cylindrical shells and cones.
[See UW-16(c)(1).]
fr p strength reduction factor, not greater than 1.0 [see
UG-41(a)]
fr1 p Sn /Sv for nozzle wall inserted through the vessel wall
fr1 p 1.0 for nozzle wall abutting the vessel wall and
for nozzles shown in Fig. UG-40, sketch (j), (k),
(n) and (o).
fr 2 p Sn /Sv
fr3 p (lesser of Sn or Sp) /Sv
fr4 p Sp /Sv
h p distance nozzle projects beyond the inner surface
of the vessel wall. (Extension of the nozzle beyond
the inside surface of the vessel wall is not limited;
however, for reinforcement calculations, credit
shall not be taken for material outside the limits
of reinforcement established by UG-40.)
K1 p spherical radius factor (see definition of tr and
Table UG-37)
L p length of projection defining the thickened portion
of integral reinforcement of a nozzle neck beyond
the outside surface of the vessel wall [see Fig.
UG-40 sketch (e)]
P p internal design pressure (see UG-21), psi (MPa)
R p inside radius of the shell course under consideration
Rn p inside radius of the nozzle under consideration
S p allowable stress value in tension (see UG-23), psi
(MPa)
Sn p allowable stress in nozzle, psi (MPa) (see S above)
Sp p allowable stress in reinforcing element (plate), psi
(MPa) (see S above)
Sv p allowable stress in vessel, psi (MPa) (see S above)
(b) General. The rules in this paragraph apply to all
openings other than:
(1) small openings covered by UG-36(c)(3);
(2) openings in flat heads covered by UG-39;
(3) openings designed as reducer sections covered by
UG-36(e);
(4) large head openings covered by UG-36(b)(2);
(5) tube holes with ligaments between them conforming to the rules of UG-53.
Reinforcement shall be provided in amount and distribution such that the area requirements for reinforcement are
satisfied for all planes through the center of the opening
and normal to the vessel surface. For a circular opening
in a cylindrical shell, the plane containing the axis of the
shell is the plane of greatest loading due to pressure. Not
less than half the required reinforcement shall be on each
side of the centerline of single openings.
25
43
In the corroded condition, see UG-16(e).
2010 SECTION VIII — DIVISION 1
FIG. UG-38 MINIMUM DEPTH FOR FLANGE OF
FLUED-IN OPENINGS
(c) Design for Internal Pressure. The total crosssectional area of reinforcement A required in any given
plane through the opening for a shell or formed head under
internal pressure shall be not less than
Minimum depth of flange: the
smaller of 3tr or tr + 3 in. (75 mm)
when d exceeds 6 in. (150 mm)
A p dtr F + 2tn tr F(1 − fr1 )
(d) Design for External Pressure
(1) The reinforcement required for openings in single-walled vessels subject to external pressure need be
only 50% of that required in (c) above, where tr is the
wall thickness required by the rules for vessels under
external pressure and the value of F shall be 1.0 in all
external pressure reinforcement calculations.
(2) The reinforcement required for openings in each
shell of a multiple-walled vessel shall comply with (1)
above when the shell is subject to external pressure, and
with (c) above when the shell is subject to internal pressure,
regardless of whether or not there is a common nozzle
secured to more than one shell by strength welds.
(e) Design for Alternate Internal and External Pressure.
Reinforcement of vessels subject to alternate internal and
external pressures shall meet the requirements of (c) above
for internal pressure and of (d) above for external pressure.
(f) Details and formulas for required area and available
area are given in Fig. UG-37.1.
(g) Reinforcing plates and saddles of nozzles attached
to the outside of a vessel shall be provided with at least
one telltale hole [maximum size NPS 1⁄4 (DN 8) tap] that
may be tapped for a preliminary compressed air and soapsuds test for tightness of welds that seal off the inside of
the vessel. These telltale holes may be left open or may
be plugged when the vessel is in service. If the holes are
plugged, the plugging material used shall not be capable
of sustaining pressure between the reinforcing plate and
the vessel wall.
(h) Segmental reinforcing elements are allowed provided the individual segments are joined by full penetration
butt welds. These butt welds shall comply with all the
applicable requirements of Part UW. Unless the provisions
given below are satisfied, the area A 5 as defined in
Fig. UG-37.1 shall be multiplied by 0.75. The area A5 does
not require any reduction if one of the following is satisfied:
(1) Each butt weld is radiographed or ultrasonically
examined to confirm full penetration, or
(2) For openings in cylinders, the weld is oriented at
least 45 deg from the longitudinal axis of the cylinder.
Each segment of the reinforcing element shall have a
clear path to a telltale hole and shall be tested as required
by UG-37(g).
(i) The reinforcement rules in this Division are applicable for internal or external pressure and do not address the
requirements for openings under the action of externally
applied loadings (such as pipe reactions). When externally
applied loadings are to be considered, see U-2(g).
d
UG-38
FLUED OPENINGS IN SHELLS AND
FORMED HEADS
(a) Flued openings in shells and formed heads made by
inward or outward forming of the head plate shall meet the
requirements for reinforcement in UG-37. The thickness of
the flued flange shall also meet the requirements of UG-27
and / or UG-28, as applicable, where L as used in UG-28
is the minimum depth of flange as shown in Fig. UG-38.
The minimum thickness of the flued flange on a vessel
subject to both internal and external pressure shall be the
larger of the two thicknesses as determined above.
(b) The minimum depth of flange of a flued in opening
exceeding 6 in. (150 mm) in any inside dimension, when
not stayed by an attached pipe or flue, shall equal 3tr or
(tr + 3 in.) (for SI units, tr + 75 mm), whichever is less,
where tr is the required shell or head thickness. The depth
of flange shall be determined by placing a straight edge
across the side opposite the flued opening along the major
axis and measuring from the straightedge to the edge of
the flanged opening (see Fig. UG-38).
(c) There is no minimum depth of flange requirement
for flued out openings.
(d) The minimum width of bearing surface for a gasket
on a self-sealing flued opening shall be in accordance with
UG-46(j).
UG-39
REINFORCEMENT REQUIRED FOR
OPENINGS IN FLAT HEADS
UG-39(a) General. The rules in this paragraph apply
to all openings in flat heads except opening(s) that do not
exceed the size and spacing limits in UG-36(c)(3) and do
not exceed one-fourth the head diameter or shortest span.
UG-39(b) Single and multiple openings in flat heads
that have diameters equal to or less than one-half the head
diameter may be reinforced as follows:
44
2010 SECTION VIII — DIVISION 1
UG-39(b)(1) Flat heads that have a single opening
with a diameter that does not exceed one-half the head
diameter or shortest span, as defined in UG-34, shall have
a total cross-sectional area of reinforcement for all planes
through the center of the opening not less than that given
by the formula
Appendix 14. Multiple rim openings shall meet spacing
rules of (b)(2) and (b)(3) above. Alternatively, the head
thickness that meets the rules of Appendix 14 may be
increased by multiplying it by the square root of two (1.414)
if only a single opening is placed in the rim space or if
spacing p between two such openings is twice or more
than their average diameter. For spacing less than twice
their average diameter, the thickness that satisfies Appendix 14 shall be divided by the square root of efficiency
factor e, where e is defined in (e)(2) below.
The rim opening(s) shall not be larger in diameter than
one-quarter the differences in head diameter less central
opening diameter. The minimum ligament width U shall
not be less than one-quarter the diameter of the smaller of
the two openings in the pair. A minimum ligament width
of one-quarter the diameter of the rim opening applies to
ligaments designated as U2 , U4 , U3 , and U5 in Fig. UG-39.
UG-39(c)(3) When the large opening is any other
type than that described in (c)(1) above, there are no specific rules given. Consequently, the requirements of U-2(g)
shall be met.
UG-39(d) As an alternative to (b)(1) above, the thickness of flat heads and covers with a single opening with
a diameter that does not exceed one-half the head diameter
may be increased to provide the necessary reinforcement
as follows:
UG-39(d)(1) In Formula (1) or (3) of UG-34(c), use
2C or 0.75 in place of C, whichever is the lesser; except
that, for sketches (b-1), (b-2), (e), (f), (g), and (i) of Fig.
UG-34, use 2C or 0.50, whichever is the lesser.
UG-39(d)(2) In Formula (2) or (5) of UG-34(c), double the quantity under the square root sign.
UG-39(e) Multiple openings none of which have diameters exceeding one-half the head diameter and no pair
having an average diameter greater than one-quarter the
head diameter may be reinforced as follows:
UG-39(e)(1) When the spacing between a pair of
adjacent openings is equal to or greater than twice the
average diameter of the pair, and this is so for all opening
pairs, the head thickness may be determined by rules in
(d) above.
UG-39(e)(2) When the spacing between adjacent
openings in a pair is less than twice but equal to or greater
than 11⁄4 the average diameter of the pair, the required head
thickness shall be that determined by (d) above multiplied
by a factor h, where
A p 0.5dt + ttn (1 − fr1)
where d, tn, and fr1 are defined in UG-37 and t in UG-34.
UG-39(b)(2) Multiple openings none of which have
diameters exceeding one-half the head diameter and no
pair having an average diameter greater than one-quarter
the head diameter may be reinforced individually as
required by (1) above when the spacing between any pair
of adjacent openings is equal to or greater than twice the
average diameter of the pair.
When spacing between adjacent openings is less than
twice but equal to or more than 11⁄4 the average diameter
of the pair, the required reinforcement for each opening
in the pair, as determined by (1) above, shall be summed
together and then distributed such that 50% of the sum is
located between the two openings. Spacings of less than
11⁄4 the average diameter of adjacent openings shall be
treated by rules of U-2(g).
UG-39(b)(3) In no case shall the width of ligament
between two adjacent openings be less than one-quarter
the diameter of the smaller of the two openings in the pair.
The width of ligament between the edge of any one opening
and the edge of the flat head (such as U3 or U5 in Fig.
UG-39) shall not be less than one-quarter the diameter of
that one opening.
UG-39(c) Flat heads that have an opening with a diameter that exceeds one-half the head diameter or shortest
span, as defined in UG-34, shall be designed as follows:
UG-39(c)(1) When the opening is a single, circular
centrally located opening in a circular flat head, the head
shall be designed according to Appendix 14 and related
factors in Appendix 2. The head-to-shell junction may be
integral, as shown in Fig. UG-34 sketches (a), (b-1), (b2), (d), and (g). The head may also be attached by a butt
weld or a full-penetration corner weld similar to the joints
shown in Fig. UW-13.2 sketches (a), (b), (c), (d), (e), or
(f). The large centrally located opening may have a nozzle
that is integrally formed or integrally attached by a full
penetration weld or may be plain without an attached nozzle or hub. The head thickness does not have to be calculated by UG-34 rules. The thickness that satisfies all the
requirements of Appendix 14 meets the requirements of
the Code.
UG-39(c)(2) Opening(s) may be located in the rim
space surrounding the central opening. See Fig. UG-39.
Such openings may be reinforced by area replacement in
accordance with the formula in (b)(1) above using as a
required head thickness the thickness that satisfies rules of
h p 冪0.5 /e
e p [( p − dave) /p]smallest
where
dave p average diameter of the same two adjacent
openings
45
2010 SECTION VIII — DIVISION 1
e p smallest ligament efficiency of adjacent opening
pairs in the head
p p center-to-center spacing of two adjacent openings
All metal in the nozzle wall extending inside the vessel
wall A3 may be included after proper deduction for corrosion allowance on all the exposed surface is made. No
allowance shall be taken for the fact that a differential
pressure on an inwardly extending nozzle may cause opposing stress to that of the stress in the shell around the
opening:
(3) metal in attachment welds A4 and metal added as
reinforcement A5.
(e) With the exception of studding outlet type flanges
and the straight hubs of forged nozzle flanges [see
UG-44(i)], bolted flange material within the limits of reinforcement shall not be considered to have reinforcing value.
UG-39(e)(3) Spacings of less than 11⁄4 the average
diameter of adjacent openings shall be treated by rules of
U-2(g).
UG-39(e)(4) In no case shall the width of ligament
between two adjacent openings be less than one-quarter
the diameter of the smaller of the two openings in the pair.
UG-39(e)(5) The width of ligament between the edge
of any one opening and the edge of the flat head (such as
U3 or U5 in Fig. UG-39) shall not be less than one-quarter
the diameter of that one opening.
UG-40
UG-41
LIMITS OF REINFORCEMENT
STRENGTH OF REINFORCEMENT
(a) Material used for reinforcement shall have an allowable stress value equal to or greater than that of the material
in the vessel wall, except that when such material is not
available, lower strength material may be used, provided
the area of reinforcement is increased in inverse proportion
to the ratio of the allowable stress values of the two materials to compensate for the lower allowable stress value of
the reinforcement. No credit may be taken for the additional
strength of any reinforcement having a higher allowable
stress value than that of the vessel wall. Deposited weld
metal outside of either the vessel wall or any reinforcing
pad used as reinforcement shall be credited with an allowable stress value equivalent to the weaker of the materials
connected by the weld. Vessel-to-nozzle or pad-to-nozzle
attachment weld metal within the vessel wall or within the
pad may be credited with a stress value equal to that of
the vessel wall or pad, respectively.
(b) On each side of the plane defined in UG-40(a),
the strength of the attachment joining the vessel wall and
reinforcement or any two parts of the attached reinforcement shall be at least equal to the smaller of:
(1) the strength in tension of the cross section of the
element or elements of reinforcement being considered
(see W1-1, W2-2, and W3-3 of Fig. UG-41.1 for examples
and L-7 for numerical examples);
(2) the strength in tension of the area defined in
UG-37 less the strength in tension of the reinforcing area
that is integral in the vessel wall as permitted by
UG-40(d)(1) (see W of Fig. UG-41.1 for examples and L-7
for numerical examples);
(3) for welded attachments, see UW-15 for exemptions to strength calculations.
(c) The strength of the attachment joint shall be considered for its entire length on each side of the plane of
the area of reinforcement defined in UG-40. For obround
openings, consideration shall also be given to the strength
of the attachment joint on one side of the plane transverse
(a) The boundaries of the cross sectional area in any
plane normal to the vessel wall and passing through the
center of the opening within which metal must be located
in order to have value as reinforcement are designated as
the limits of reinforcement for that plane (see
Fig. UG-37.1). Figure UG-40 depicts thicknesses t, te, and
tn, or ti and diameter d used in establishing the limits of
reinforcement. All dimensions are in the corroded condition; for nomenclature, see UG-37(a).
(b) The limits of reinforcement, measured parallel to
the vessel wall, shall be at a distance, on each side of the
axis of the opening, equal to the greater of the following:
(1) the diameter d of the finished opening;
(2) the radius Rn of the finished opening plus the
vessel wall thickness t, plus the nozzle wall thickness tn.
(c) The limits of reinforcement, measured normal to the
vessel wall, shall conform to the contour of the surface at
a distance from each surface equal to the smaller of the
following:
(1) 21⁄2 times the vessel wall thickness t;
(2) 21⁄2 times the nozzle wall thickness tn plus the
thickness te as defined in Fig. UG-40.
(d) Metal within the limits of reinforcement that may
be considered to have reinforcing value shall include the
following:
(1) metal in the vessel wall over and above the thickness required to resist pressure and the thickness specified
as corrosion allowance. the area in the vessel wall available
as reinforcement is the larger of the values of A1 given by
the formulas in Fig. UG-37.1.
(2) metal over and above the thickness required to
resist pressure and the thickness specified as corrosion
allowance in that part of a nozzle wall extending outside
the vessel wall. The maximum area in the nozzle wall
available as reinforcement is the smaller of the values of
A2 given by the formulas in Fig. UG-37.1.
46
2010 SECTION VIII — DIVISION 1
FIG. UG-39 MULTIPLE OPENINGS IN RIM OF HEADS WITH A LARGE CENTRAL OPENING
47
2010 SECTION VIII — DIVISION 1
FIG. UG-40 SOME REPRESENTATIVE CONFIGURATIONS DESCRIBING THE REINFORCEMENT DIMENSION t e
AND THE OPENING DIMENSION d
48
2010 SECTION VIII — DIVISION 1
FIG. UG-40 SOME REPRESENTATIVE CONFIGURATIONS DESCRIBING THE REINFORCEMENT
DIMENSION t e AND THE OPENING DIMENSION d (CONT’D)
tn
d
3
d
tn
1
te
d
d
tn
30 deg
t
30 deg
L
(f)
te = 0
te
tn
t
t
30 deg
45 deg max.
30 deg max.
t
tx
(e)
d
te
(e-2)
(e-1)
GENERAL NOTE [sketches (e), (e-1), and (e-2)]:
If L 2.5tx, use sketch (e-1)
If L 2.5tx, use sketch (e-2)
t
(g)
tn
3/ in (19 mm)
4
R min.
30 deg
tn
tn
d
te
te
t
d
t
te
t
d
te = 0.73R
(h)
(j)
(i)
d
tn
d
tn
tn
30 deg
te
t
t
t
d
(k)
(l)
(m)
tn
tn
t
t
d
d
(n)
(o)
49
2010 SECTION VIII — DIVISION 1
FIG. UG-41.1 NOZZLE ATTACHMENT WELD LOADS AND WELD STRENGTH PATHS TO BE CONSIDERED
50
2010 SECTION VIII — DIVISION 1
FIG. UG-41.1 NOZZLE ATTACHMENT WELD LOADS AND WELD STRENGTH PATHS TO BE CONSIDERED (CONT’D)
to the parallel sides of the opening that passes through the
center of the semicircular end of the opening.
(d) For detailed requirements for welded and brazed
reinforcement see the appropriate paragraphs in the Parts
devoted to these subjects (see UW-15 and UB-19).
UG-42
section is to be considered as applying to more than one
opening, nor to be considered more than once in a combined area.
(1) The available area of the head or shell between
openings having an overlap area shall be proportioned
between the two openings by the ratio of their diameters.
(2) For cylinders and cones, if the area of reinforcement between the two openings is less than 50% of the
total required for the two openings, the supplemental rules
of 1-7(a) and (c) shall be used.
(3) A series of openings all on the same centerline
shall be treated as successive pairs of openings.
(b) When more than two openings are spaced as in (a)
above [see Fig. UG-42 sketch (b)], and are to be provided
with a combined reinforcement, the minimum distance
between centers of any two of these openings shall be 11⁄3
times their average diameter, and the area of reinforcement
REINFORCEMENT OF MULTIPLE
OPENINGS
(See UG-39 for multiple openings in flat heads.)
(a) When any two openings are spaced such that their
limits of reinforcement overlap [see Fig. UG-42 sketch
(a)], the two openings shall be reinforced in the plane
connecting the centers, in accordance with the rules of
UG-37, UG-38, UG-40, and UG-41 with a combined reinforcement that has an area not less than the sum of the
areas required for each opening. No portion of the cross
51
2010 SECTION VIII — DIVISION 1
FIG. UG-42 EXAMPLES OF MULTIPLE OPENINGS
between any two openings shall be at least equal to 50%
of the total required for the two openings. If the distance
between centers of two such openings is less than 11⁄3 times
their average diameter, no credit for reinforcement shall
be taken for any of the material between these openings.
Such openings must be reinforced as described in (c) below.
UG-43
METHODS OF ATTACHMENT OF
PIPE AND NOZZLE NECKS TO
VESSEL WALLS
(a) General. Nozzles may be attached to the shell or
head of a vessel by any of the methods of attachment given
in this paragraph, except as limited in UG-36.
(b) Welded Connections. Attachment by welding shall
be in accordance with the requirements of UW-15 and
UW-16.
(c) Brazed Connections. Attachment by brazing shall
be in accordance with the requirements of UB-17 through
UB-19.
(d) Studded Connections. Connections may be made by
means of studs. The vessel shall have a flat surface
machined on the shell, or on a built-up pad, or on a properly
attached plate or fitting. The distance from the inside surface of the vessel to the bottom of a drilled hole to be
tapped shall not be less than the corrosion allowance plus
one-fourth of the minimum required wall thickness. Weld
metal may be added to the inside surface of the vessel to
maintain this distance (see UW-42). The tapped holes shall
also conform to the requirements of (g) below. Studded
connections shall meet the requirements for reinforcement
in UG-36 through UG-42.
(c) Alternatively, any number of adjacent openings, in
any arrangement, may be reinforced by using an assumed
opening enclosing all such openings. The limits for reinforcement of the assumed opening shall be those given in
UG-40(b)(1) and (c)(1). The nozzle walls of the actual
openings shall not be considered to have reinforcing value.
For cylinders and cones, when the diameter of the assumed
opening exceeds the limits in UG-36(b)(1), the supplemental rules of 1-7(a) and (c) shall also be used.
(d) When a group of openings is reinforced by a thicker
section butt welded into the shell or head, the edges of the
inserted section shall be tapered as prescribed in UW-9(c).
(e) When a series of two or more openings in a cylindrical or conical shell are arranged in a regular pattern, reinforcement of the openings may be provided per the rules
of ligaments in UG-53.
52
2010 SECTION VIII — DIVISION 1
TABLE UG-43
MINIMUM NUMBER OF PIPE THREADS FOR CONNECTIONS
Size of Pipe Connection,
NPS (DN)
Threads Engaged
Min. Plate Thickness Required,
in. (mm)
1
⁄2 & 3⁄4 (DN 15 & 20)
1, 11⁄4 & 11⁄2 (DN 25, 32, & 40)
2 (DN 50)
21⁄2 & 3 (DN 65 & 80)
4–6 (DN 100–150)
8 (DN 200)
10 (DN 250)
12 (DN 300)
6
7
8
8
10
12
13
14
0.43 (11.0)
0.61 (15)
0.70 (18)
1.0 (25)
1.25 (32)
1.5 (38)
1.62 (41)
1.75 (45)
(e) Threaded Connections. Pipes, tubes, and other
threaded connections that conform to the ASME Standard
for Pipe Threads, General Purpose, Inch (ASME B1.20.1)
may be screwed into a threaded hole in a vessel wall,
provided the pipe engages the minimum number of threads
specified in Table UG-43 after allowance has been made
for curvature of the vessel wall. The thread shall be a
standard taper pipe thread except that a straight thread of
at least equal strength may be used if other sealing means to
prevent leakage are provided. A built-up pad or a properly
attached plate or fitting may be used to provide the metal
thickness and number of threads required in Table UG-43,
or to furnish reinforcement when required.
Threaded connections larger than 4 in. pipe size
(DN 100) shall not be used in vessels that contain liquids
having a flash-point below 110°F (43°C), or flammable
vapors, or flammable liquids at temperatures above that at
which they boil under atmospheric pressure.
Threaded connections larger than 3 in. pipe size (DN 80)
shall not be used when the maximum allowable working
pressure exceeds 125 psi (0.8 MPa), except that this 3 in.
pipe size (DN 80) restriction does not apply to plug closures
used for inspection openings, end closures, or similar purposes, or to integrally forged openings in vessel heads
meeting the requirement of UF-43.
(f) Expanded Connections. A pipe, tube, or forging may
be attached to the wall of a vessel by inserting through an
unreinforced opening and expanding into the shell, provided the diameter is not greater than 2 in. pipe size
(DN 50). A pipe, tube, or forging not exceeding 6 in.
(150 mm) in outside diameter may be attached to the wall
of a vessel by inserting through a reinforced opening and
expanding into the shell.
Such connections shall be:
(1) firmly rolled in and beaded; or
(2) rolled in, beaded, and seal-welded around the edge
of the bead; or
(3) expanded and flared not less than 1⁄8 in. (3 mm)
over the diameter of the hole; or
(4) rolled, flared, and welded; or
(5) rolled and welded without flaring or beading, provided:
(a) the ends extend at least 1⁄4 in. (6 mm), but no
more than 3⁄8 in. (10 mm), through the shell;
(b) the throat of the weld is at least 3⁄16 in. (5 mm),
but no more than 5⁄16 in. (8 mm).
When the tube or pipe does not exceed 11⁄2 in. (38 mm)
in outside diameter, the shell may be chamfered or recessed
to a depth at least equal to the thickness of the tube or
pipe and the tube or pipe may be rolled into place and
welded. In no case shall the end of the tube or pipe extend
more than 3⁄8 in. (10 mm) beyond the shell.
Grooving of shell openings in which tubes and pipe are
to be rolled or expanded is permissible.
Expanded connections shall not be used as a method of
attachment to vessels used for the processing or storage
of flammable and /or noxious gases and liquids unless the
connections are seal-welded.
(g) Where tapped holes are provided for studs, the
threads shall be full and clean and shall engage the stud
for a length not less than the larger of ds or
maximum allowable stress value of
stud material at design temperature
0.75 ds ⴛ
maximum allowable stress value of
tapped material at design temperature
in which ds is the nominal diameter of the stud, except
that the thread engagement need not exceed 11⁄2ds.
UG-44
FLANGES AND PIPE FITTINGS
The following standards covering flanges and pipe fittings are acceptable for use under this Division in accordance with the requirements of UG-11. Pressure–
temperature ratings shall be in accordance with the appropriate standard except that the pressure–temperature ratings
for ASME B16.9 and ASME B16.11 fittings shall be calculated as for straight seamless pipe in accordance with the
rules of this Division including the maximum allowable
stress for the material. The thickness tolerance of the
ASME standards shall apply.
53
2010 SECTION VIII — DIVISION 1
UG-44(a) ASME B16.5, Pipe Flanges and Flanged Fittings [see UG-11(a)(2)]
UG-44(b) ASME B16.9, Factory-Made Wrought
Buttwelding Fittings
UG-44(c) ASME B16.11, Forged Fittings, SocketWelding and Threaded
UG-44(d) ASME B16.15, Cast Bronze Threaded Fittings, Classes 125 and 250
UG-44(e) ASME B16.20, Metallic Gaskets for Pipe
Flanges — Ring-Joint, Spiral-Wound, and Jacketed
UG-44(f) ASME B16.24, Cast Copper Alloy Pipe
Flanges and Flanged Fittings, Class 150, 300, 400, 600,
900, 1500, and 2500
UG-44(g) ASME B16.42, Ductile Iron Pipe Flanges and
Flanged Fittings, Class 150 and 300
UG-44(h) ASME B16.47, Large Diameter Steel
Flanges, NPS 26 Through NPS 60
UG-44(i) A forged nozzle flange may use the ASME
B16.5/B16.47 pressure–temperature ratings for the flange
material being used, provided all of the following are met:
UG-44(i)(1) For ASME B16.5 applications, the
forged nozzle flange shall meet all dimensional requirements of a flanged fitting given in ASME B16.5 with the
exception of the inside diameter. The inside diameter of the
forged nozzle flange shall not exceed the inside diameter of
the same size lap joint flange given in ASME B16.5. For
ASME B16.47 applications, the inside diameter shall not
exceed the weld hub diameter A given in the ASME B16.47
tables.
UG-44(i)(2) For ASME B16.5 applications, the outside diameter of the forged nozzle neck shall be at least
equal to the hub diameter of the same size and class ASME
B16.5 lap joint flange. For ASME B16.47 applications, the
outside diameter of the hub shall at least equal the X diameter given in the ASME B16.47 tables. Larger hub diameters
shall be limited to nut stop diameter dimensions. See Fig.
2-4 sketches (12) and (12a).
(10)
UG-45
where
ta p minimum neck thickness required for internal
and external pressure using UG-27 and UG28 (plus corrosion allowance), as applicable.
The effects of external forces and moments
from supplemental loads (see UG-22) shall be
considered. Shear stresses caused by UG-22
loadings shall not exceed 70% of the allowable
tensile stress for the nozzle material.
tb1 p for vessels under internal pressure, the thickness (plus corrosion allowance) required for
pressure (assuming E p 1.0) for the shell or
head at the location where the nozzle neck or
other connection attaches to the vessel but in
no case less than the minimum thickness specified for the material in UG-16(b).
tb2 p for vessels under external pressure, the thickness (plus corrosion allowance) obtained by
using the external design pressure as an equivalent internal design pressure (assuming E p
1.0) in the formula for the shell or head at
the location where the nozzle neck or other
connection attaches to the vessel but in no case
less than the minimum thickness specified for
the material in UG-16(b).
tb3 p the thickness given in Table UG-45 plus the
thickness added for corrosion allowance.
tUG-45 p minimum wall thickness of nozzle necks
NOTE: For applications of rules in UG-45, refer to Nonmandatory
Appendix L.
UG-46
INSPECTION OPENINGS27
(a) All pressure vessels for use with compressed air and
those subject to internal corrosion or having parts subject
to erosion or mechanical abrasion (see UG-25), except as
permitted otherwise in this paragraph, shall be provided
with suitable manhole, handhole, or other inspection openings for examination and cleaning.
Compressed air as used in this paragraph is not intended
to include air that has had moisture removed to provide
an atmospheric dew point of −50°F (−46°C) or less.
Inspection openings may be omitted in vessels covered
in UG-46(b), and in the shell side of fixed tubesheet heat
exchangers. When inspection openings are not provided,
the Manufacturer’s Data Report shall include one of the
following notations under remarks:
(1) “UG-46(b)” when telltale holes are used in lieu
of inspection openings;
(2) “UG-46(a)” when inspection openings are omitted in fixed tubesheet heat exchangers;
NOZZLE NECK THICKNESS
The minimum wall thickness of nozzle necks shall be
determined as given below.
For access openings and openings used only for
inspection:
t UG-45 p ta
For other nozzles:
Determine tb.
t b p min 关tb3, max 共tb1, tb2兲兴
26
DELETED
All dimensions given, for size of vessel on which inspection openings
are required, are nominal.
27
t UG-45 p max 共ta, tb兲
54
2010 SECTION VIII — DIVISION 1
(10)
TABLE UG-45
NOZZLE MINIMUM THICKNESS REQUIREMENTS
(e) Vessels less than 16 in. (400 mm) and over 12 in.
(300 mm) I.D. shall have at least two handholes or two
threaded pipe plug inspection openings of not less than
NPS 11⁄2 (DN 40) except as permitted by the following:
when vessels less than 16 in. (400 mm) and over 12 in.
(300 mm) I.D. are to be installed so that inspection cannot
be made without removing the vessel from the assembly,
openings for inspection only may be omitted provided there
are at least two removable pipe connections of not less
than NPS 11⁄2 (DN 40).
(f) Vessels that require access or inspection openings
shall be equipped as follows.28
(1) All vessels less than 18 in. (450 mm) and over
12 in. (300 mm) I.D. shall have at least two handholes or
two plugged, threaded inspection openings of not less than
NPS 11⁄2 (DN 40).
(2) All vessels 18 in. (450 mm) to 36 in. (900 mm),
inclusive, I.D. shall have a manhole or at least two handholes or two plugged, threaded inspection openings of not
less than NPS 2 (DN 50).
(3) All vessels over 36 in. (900 mm) I.D. shall have
a manhole, except that those whose shape or use makes
one impracticable shall have at least two handholes 4 in.
ⴛ 6 in. (100 mm ⴛ 150 mm) or two equal openings of
equivalent area.
(4) When handholes or pipe plug openings are permitted for inspection openings in place of a manhole, one
handhole or one pipe plug opening shall be in each head
or in the shell near each head.
(5) Openings with removable heads or cover plates
intended for other purposes may be used in place of the
required inspection openings provided they are equal at
least to the size of the required inspection openings.
(6) A single opening with removable head or cover
plate may be used in place of all the smaller inspection
openings provided it is of such size and location as to
afford at least an equal view of the interior.
(7) Flanged and /or threaded connections from which
piping, instruments, or similar attachments can be removed
may be used in place of the required inspection openings
provided that:
(a) the connections are at least equal to the size of
the required openings; and
(b) the connections are sized and located to afford
at least an equal view of the interior as the required inspection openings.
(g) When inspection or access openings are required,
they shall comply at least with the following requirements:
(1) An elliptical or obround manhole shall be not less
than 12 in. ⴛ 16 in. (300 mm ⴛ 400 mm). A circular
manhole shall be not less than 16 in. (400 mm) I.D.
Minimum Wall Thickness
[see UG-16(d)]
Nominal Size
in.
mm
0.060
0.077
0.080
0.095
0.099
1.51
1.96
2.02
2.42
2.51
NPS
NPS
NPS
NPS
NPS
1
NPS
NPS
NPS
NPS
NPS
1 (DN 25)
11⁄4 (DN 32)
11⁄2 (DN 40)
2 (DN 50)
21⁄2 (DN 65)
0.116
0.123
0.127
0.135
0.178
2.96
3.12
3.22
3.42
4.52
NPS
NPS
NPS
NPS
NPS
3 (DN 80)
31⁄2 (DN 90)
4 (DN 100)
5 (DN 125)
6 (DN 150)
0.189
0.198
0.207
0.226
0.245
4.80
5.02
5.27
5.73
6.22
0.282
0.319
0.328
7.16
8.11
8.34
⁄8
⁄4
3
⁄8
1
⁄2
3
⁄4
1
(DN
(DN
(DN
(DN
(DN
6)
8)
10)
15)
20)
NPS 8 (DN 200)
NPS 10 (DN 250)
≥ NPS 12 (DN 300)
GENERAL NOTE: For nozzles having a specified outside diameter
not equal to the outside diameter of an equivalent standard NPS (DN)
size, the NPS (DN) size chosen from the table shall be one having an
equivalent outside diameter larger than the nozzle outside diameter.
(3) “UG-46(c),” “UG-46(d),” or “UG-46(e)” when
provision for inspection is made in accordance with one
of these paragraphs;
(4) the statement “for noncorrosive service.”
(b) When provided with telltale holes complying with
the provisions of UG-25, inspection openings as required
in (a) above may be omitted in vessels not over 36 in.
(900 mm). I.D. that are subject only to corrosion, provided
that the holes are spaced one hole per 10 ft2 (0.9 m2)
(or fraction thereof) of internal vessel surface area where
corrosion is expected with a minimum of four uniformly
spaced holes per vessel. This provision does not apply to
vessels for compressed air.
(c) Vessels over 12 in. (300 mm) I.D. under air pressure
that also contain, as an inherent requirement of their operation, other substances that will prevent corrosion need not
have openings for inspection only, provided the vessel
contains suitable openings through which inspection can
be made conveniently, and provided such openings are
equivalent in size and number to the requirements for
inspection openings in (f) below.
(d) For vessels 12 in. (300 mm) or less in inside diameter, openings for inspection only may be omitted if there
are at least two removable pipe connections not less than
NPS 3⁄4 (DN 20).
28
55
Dimensions referred to are nominal.
2010 SECTION VIII — DIVISION 1
FIG. UG-47 ACCEPTABLE PROPORTIONS FOR ENDS
OF STAYS
(2) A handhole opening shall be not less than 2 in.
ⴛ 3 in. (50 mm ⴛ 75 mm), but should be as large as is
consistent with the size of the vessel and the location of
the opening.
(h) All access and inspection openings in a shell or
unstayed head shall be designed in accordance with the
rules of this Division for openings.
(i) When a threaded opening is to be used for inspection
or cleaning purposes, the closing plug or cap shall be of
a material suitable for the pressure and no material shall be
used at a temperature exceeding the maximum temperature
allowed in this Division for that material. The thread shall
be a standard taper pipe thread except that a straight thread
of at least equal strength may be used if other sealing
means to prevent leakage are provided.
(j) Manholes of the type in which the internal pressure
forces the cover plate against a flat gasket shall have a
minimum gasket bearing width of 11⁄16 in. (17 mm).
BRACED AND STAYED SURFACES
UG-47
BRACED AND STAYED SURFACES
(a) The minimum thickness and maximum allowable
working pressure for braced and stayed flat plates and those
parts that, by these rules, require staying as flat plates
with braces or staybolts of uniform diameter symmetrically
spaced, shall be calculated by the following formulas:
tpp
Pp
冪
P
SC
t 2 SC
p2
(1)
(2)
P
p
where
C p 2.1 for welded stays or stays screwed through
plates not over 7⁄16 in. (11 mm) in thickness with
ends riveted over
p 2.2 for welded stays or stays screwed through
plates over 7⁄16 in. (11 mm) in thickness with ends
riveted over
p 2.5 for stays screwed through plates and fitted
with single nuts outside of plate, or with inside
and outside nuts, omitting washers; and for stays
screwed into plates as shown in Fig. UG-47
sketch (b)
p 2.8 for stays with heads not less than 1.3 times
the diameter of the stays screwed through plates
or made a taper fit and having the heads formed
on the stays before installing them, and not riveted
over, said heads being made to have a true bearing
on the plate
S
t
p 3.2 for stays fitted with inside and outside nuts and
outside washers where the diameter of washers is
not less than 0.4p and thickness not less than t
p internal design pressure (see UG-21)
p maximum pitch. The maximum pitch is the greatest distance between any set of parallel straight
lines passing through the centers of staybolts in
adjacent rows. Each of the three parallel sets running in the horizontal, the vertical, and the inclined
planes shall be considered.
p maximum allowable stress value in tension (see
UG-23)
p minimum thickness of plate
(b) The minimum thickness of plates to which stays
may be applied, in other than cylindrical or spherical outer
shell plates, shall be 5⁄16 in. (8 mm) except for welded
construction covered by UW-19 or Appendix 17.
(c) If a stayed jacket extends completely around a cylindrical or spherical vessel, or completely covers a formed
head, it shall meet the requirements given in (a) above,
and shall also meet the applicable requirements for shells
or heads in UG-27(c) and (d) and UG-32. In addition, where
any nozzle or other opening penetrates the cylindrical or
56
2010 SECTION VIII — DIVISION 1
spherical vessel, or completely covered head, and the
jacket, the vessel or formed head shall be designed in
accordance with UG-37(d)(2).
(d) When two plates are connected by stays and but one
of these plates requires staying, the value of C shall be
governed by the thickness of the plate requiring staying.
(e) Acceptable proportions for the ends of through stays
with washers are indicated in Fig. UG-47 sketch (a). See
UG-83.
(f) The maximum pitch shall be 81⁄2 in. (220 mm), except
that for welded-in staybolts the pitch may be greater provided it does not exceed 15 times the diameter of the
staybolt.
(g) When the staybolting of shells is unsymmetrical by
reason of interference with butt straps or other construction,
it is permissible to consider the load carried by each staybolt as the area calculated by taking the distance from the
center of the spacing on one side of the bolt to the center
of the spacing on the other side.
load carried by a stay is the product of the area supported
by the stay and the maximum allowable working pressure.
(c) Stays made of parts joined by welding shall be
checked for strength using a joint efficiency of 60% for
the weld.
UG-48
(b) When a cylindrical shell is drilled for tubes in a line
parallel to the axis of the shell for substantially the full
length of the shell as shown in Figs. UG-53.1 through
UG-53.3, the efficiency of the ligaments between the tube
holes shall be determined as follows:
(1) When the pitch of the tube holes on every row is
equal (see Fig. UG-53.1), the formula is
LIGAMENTS
UG-53
(a) The symbols used in the formulas and charts of this
paragraph are defined as follows:
d
n
p
p1
p′
s
p
p
p
p
p
p
p
p
STAYBOLTS
(a) The ends of staybolts or stays screwed through the
plate shall extend beyond the plate not less than two threads
when installed, after which they shall be riveted over or
upset by an equivalent process without excessive scoring
of the plates, or they shall be fitted with threaded nuts
through which the bolt or stay shall extend.
(b) The ends of steel stays upset for threading shall be
fully annealed.
(c) Requirements for welded-in staybolts are given in
UW-19.
UG-49
(2) When the pitch of tube holes on any one row is
unequal (as in Figs. UG-53.2 and UG-53.3), the formula is
p1 − nd
p efficiency of ligament
p1
LOCATION OF STAYBOLTS
(c) When the adjacent longitudinal rows are drilled as
described in (b) above, diagonal and circumferential ligaments shall also be examined. The least equivalent longitudinal efficiency shall be used to determine the minimum
required thickness and the maximum allowable working
pressure.
(d) When a cylindrical shell is drilled for holes so as
to form diagonal ligaments, as shown in Fig. UG-53.4, the
efficiency of these ligaments shall be determined by Figs.
UG-53.5 and UG-53.6. Figure UG-53.5 is used to determine the efficiency of longitudinal and diagonal ligaments
with limiting boundaries where the condition of equal efficiency of diagonal and longitudinal ligaments form one
boundary and the condition of equal efficiency of diagonal
and circumferential ligaments form the other boundary.
Figure UG-53.6 is used for determining the equivalent
longitudinal efficiency of diagonal ligaments. This efficiency is used in the formulas for setting the minimum
DIMENSIONS OF STAYBOLTS
(a) The required area of a staybolt at its minimum cross
section29 and exclusive of any allowance for corrosion
shall be obtained by dividing the load on the staybolt
computed in accordance with (b) below by the allowable
stress value for the material used, as given in Subsection
C, and multiplying the result by 1.10.
(b) Load Carried by Stays. The area supported by a stay
shall be computed on the basis of the full pitch dimensions,
with a deduction for the area occupied by the stay. The
29
diameter of tube holes
number of tube holes in length p1
longitudinal pitch of tube holes
unit length of ligament
diagonal pitch of tube holes
longitudinal dimension of diagonal pitch
p′ cos angle of diagonal with longitudinal line, deg
p−d
p efficiency of ligament
p
(a) When the edge of a flat stayed plate is flanged, the
distance from the center of the outermost stays to the inside
of the supporting flange shall not be greater than the pitch
of the stays plus the inside radius of the flange.
UG-50
LIGAMENTS
The minimum cross section is usually at the root of the thread.
57
2010 SECTION VIII — DIVISION 1
FIG. UG-53.1 EXAMPLE OF TUBE SPACING WITH PITCH OF HOLES EQUAL IN EVERY ROW
51/4
in.
51/4
in.
51/4
51/4
51/4
51/4
51/4
in.
in.
in.
in.
in.
Longitudinal line
GENERAL NOTE: 51/4 in. = 133 mm
FIG. UG-53.2 EXAMPLE OF TUBE SPACING WITH PITCH OF HOLES UNEQUAL IN EVERY SECOND ROW
51/4
in.
63/4
in.
51/4
in.
63/4
in.
51/4
in.
63/4
in.
51/4
in.
p1 = 12 in.
(305 mm)
Longitudinal line
GENERAL NOTE: 51/4 in. = 135 mm
63/4 in. = 170 mm
FIG. UG-53.3 EXAMPLE OF TUBE SPACING WITH PITCH OF HOLES VARYING
IN EVERY SECOND AND THIRD ROW
51/4
in.
63/4
in.
51/4
in.
51/4
in.
63/4
in.
51/4
in.
p1 = 291/4 in.
(745 mm)
Longitudinal line
GENERAL NOTE: 51/4 in. = 135 mm
63/4 in. = 170 mm
58
63/4
in.
51/4
in.
51/4
in.
2010 SECTION VIII — DIVISION 1
FIG. UG-53.4 EXAMPLE OF TUBE SPACING WITH
TUBE HOLES ON DIAGONAL LINES
(h) The average ligament efficiency in a cylindrical
shell, in which the tube holes are arranged along lines
parallel to the axis with either uniform or nonuniform
spacing, shall be computed by the following rules and shall
satisfy the requirements of both:30
(1) For a length equal to the inside diameter of the
shell for the position which gives the minimum efficiency,
the efficiency shall be not less than that on which the
maximum allowable working pressure is based. When the
inside diameter of the shell exceeds 60 in. (1 500 mm),
the length shall be taken as 60 in. (1 500 mm) in applying
this rule.
(2) For a length equal to the inside radius of the shell
for the position which gives the minimum efficiency, the
efficiency shall be not less than 80% of that on which the
maximum allowable working pressure is based. When the
inside radius of the shell exceeds 30 in., the length shall
be taken as 30 in. (760 mm) in applying this rule.
(i) When ligaments occur in cylindrical shells made
from welded pipe or tubes, and their calculated efficiency
is less than 85% (longitudinal) or 50% (circumferential),
the efficiency to be used in the formulas of UG-27 is the
calculated ligament efficiency. In this case, the appropriate
stress value in tension (see UG-23) may be multiplied by
the factor 1.18.
(j) Examples illustrating the application of the rules in
this paragraph are given in Appendix L.
p1 = 111/2 in.
(290 mm)
53/4 in.
(145 mm)
p' = 6.42 in.
(165 mm)
Longitudinal line
required thickness and the maximum allowable working
pressure.
(e) Figure UG-53.5 is used when either or both longitudinal and circumferential ligaments exist with diagonal
ligaments. To use Fig. UG-53.5, compute the value of
p′ /p1 and also the efficiency of the longitudinal ligament.
Next find the vertical line in the diagram corresponding to
the longitudinal efficiency of the ligament and follow this
line vertically to the point where it intersects the diagonal
line representing the ratio of p′ /p1. Then project this point
horizontally to the left, and read the diagonal efficiency of
the ligament on the scale at the edge of the diagram. The
minimum shell thickness and the maximum allowable
working pressure shall be based on the ligament that has
the lower efficiency.
(f) Figure UG-53.6 is used for holes which are not in
line, placed longitudinally along a cylindrical shell. The
diagram may be used for pairs of holes for all planes
between the longitudinal plane and the circumferential
plane. To use Fig. UG-53.6, determine the angle between
the longitudinal shell axis and the line between the centers
of the openings, , and compute the value of p′ /d. Find
the vertical line in the diagram corresponding to the value
of and follow this line vertically to the line representing
the value of p′ /d. Then project this point horizontally to
the left, and read the equivalent longitudinal efficiency of
the diagonal ligament. This equivalent longitudinal efficiency is used to determine the minimum required thickness and the maximum allowable working pressure.
(g) When tube holes in a cylindrical shell are arranged
in symmetrical groups which extend a distance greater than
the inside diameter of the shell along lines parallel to the
axis and the same spacing is used for each group, the
efficiency for one of the groups shall be not less than
the efficiency on which the maximum allowable working
pressure is based.
UG-54
SUPPORTS
(a) All vessels shall be so supported and the supporting
members shall be arranged and /or attached to the vessel
wall in such a way as to provide for the maximum imposed
loadings (see UG-22 and UG-82).
(b) Appendix G contains suggested rules for the design
of supports.
UG-55
LUGS FOR PLATFORMS, LADDERS,
AND OTHER ATTACHMENTS TO
VESSEL WALLS
(a) Lugs or clips may be welded, brazed, or bolted
to the outside or inside of the vessel to support ladders,
platforms, piping, motor or machinery mounts, and attachment of insulating jackets (see UG-22). The material of
the lugs or clips shall be in accordance with UG-4.
30
The rules in this paragraph apply to ligaments between tube holes
and not to single openings. They may give lower efficiencies in some
cases than those for symmetrical groups which extend a distance greater
than the inside diameter of the shell as covered in (e) above. When this
occurs, the efficiencies computed by the rules under (b) above shall
govern.
59
2010 SECTION VIII — DIVISION 1
FIG. UG-53.5 DIAGRAM FOR DETERMINING THE EFFICIENCY OF LONGITUDINAL AND DIAGONAL LIGAMENTS
BETWEEN OPENINGS IN CYLINDRICAL SHELLS
60
2010 SECTION VIII — DIVISION 1
FIG. UG-53.6 DIAGRAM FOR DETERMINING EQUIVALENT LONGITUDINAL EFFICIENCY OF DIAGONAL
LIGAMENTS BETWEEN OPENINGS IN CYLINDRICAL SHELLS
61
2010 SECTION VIII — DIVISION 1
(b) External piping connected to a pressure vessel shall
be installed so as not to overstress the vessel wall (see
UG-22 and UG-82).
(c) Appendix G provides guidance on the design of
attachments.
(a) Plates, edges of heads, and other parts may be cut
to shape and size by mechanical means such as machining,
shearing, grinding, or by oxygen or arc cutting. After oxygen or arc cutting, all slag and detrimental discoloration
of material which has been molten shall be removed by
mechanical means prior to further fabrication or use.
(b) Ends of nozzles or manhole necks which are to
remain unwelded in the completed vessel may be cut by
shearing provided sufficient additional material is removed
by any other method that produces a smooth finish.
(c) Exposed inside edges shall be chamfered or rounded.
method acceptable to the Inspector. The Inspector need
not witness the transfer of the marks but shall satisfy himself that it has been correctly done (see UHT-86).
(b) Where the service conditions prohibit die-stamping
for material identification, and when so specified by the
user, the materials manufacturer shall mark the required
data on the plates in a manner which will allow positive
identification upon delivery. The markings must be
recorded so that each plate will be positively identified in
its position in the completed vessel to the satisfaction of
the Inspector. Transfer of markings for material that is to
be divided shall be done as in (a) above.
(c) When material is formed into shapes by anyone other
than the Manufacturer of the completed pressure vessel,
and the original markings as required by the applicable
material specification are unavoidably cut out, or the material is divided into two or more parts, the manufacturer of
the shape shall either:
(1) transfer the original identification markings to
another location on the shape; or
(2) provide for identification by the use of a coded
marking traceable to the original required marking, using
a marking method agreed upon and described in the quality
control system of the Manufacturer of the completed pressure vessel.
Identification in accordance with UG-93, in conjunction
with the above modified marking requirements, shall be
considered sufficient to identify these shapes. Manufacturer’s Partial Data Reports and parts stamping are not a
requirement unless there has been fabrication to the shapes
that include welding, except as exempted by UG-11.
UG-77
UG-78
FABRICATION
UG-75
GENERAL
The fabrication of pressure vessels and vessel parts shall
conform to the general fabrication requirements in the following paragraphs and to the specific requirements for
Fabrication given in the applicable Parts of Subsections
B and C.
UG-76
CUTTING PLATES AND OTHER
STOCK
MATERIAL IDENTIFICATION (SEE
UG-85)
(a) Material for pressure parts preferably should be laid
out so that when the vessel is completed, one complete set
of the original identification markings required by UG-94
will be plainly visible. The pressure vessel Manufacturer
shall maintain traceability of the material to the original
identification markings by one or more of the following
methods: accurate transfer of the original identification
markings to a location where the markings will be visible
on the completed vessel; identification by a coded marking
traceable to the original required marking; or recording the
required markings using methods such as material tabulations or as built sketches which assure identification of
each piece of material during fabrication and subsequent
identification in the completed vessel. Such transfers of
markings shall be made prior to cutting except that the
Manufacturer may transfer markings immediately after cutting provided the control of these transfers is described in
his written Quality Control System (see 10-6). Except as
indicated in (b) below, material may be marked by any
REPAIR OF DEFECTS IN
MATERIALS
Defects in material may be repaired provided acceptance
by the Inspector is first obtained for the method and extent
of repairs. Defective material that cannot be satisfactorily
repaired shall be rejected.
UG-79
FORMING SHELL SECTIONS AND
HEADS
(a) Limits are provided on cold working of all carbon
and low alloy steels, nonferrous alloys, high alloy steels,
and ferritic steels with tensile properties enhanced by heat
treatment [see UCS-79(d), UHA-44(a), UNF-79(a), and
UHT-79(a)(1)].
(b) If the plates are to be rolled, the adjoining edges of
longitudinal joints of cylindrical vessels shall first be
shaped to the proper curvature by preliminary rolling or
forming in order to avoid having objectionable flat spots
along the completed joints (see UG-80).
62
(10)
2010 SECTION VIII — DIVISION 1
FIG. UG-80.1 MAXIMUM PERMISSIBLE DEVIATION FROM A CIRCULAR FORM e FOR VESSELS UNDER
EXTERNAL PRESSURE
FIG. UG-80.2 EXAMPLE OF DIFFERENCES BETWEEN
MAXIMUM AND MINIMUM INSIDE DIAMETERS IN
CYLINDRICAL, CONICAL, AND SPHERICAL SHELLS
(c) When the vessel shell section, heads, or other pressure boundary parts are cold formed by other than the
manufacturer of the vessel, the required certification for
the part shall indicate whether or not the part has been heattreated (see UCS-79, UHA-44, UNF-79, and UHT-79).
(10)
UG-80
PERMISSIBLE OUT-OF-ROUNDNESS
OF CYLINDRICAL, CONICAL, AND
SPHERICAL SHELLS
(a) Internal Pressure. The shell of a completed vessel
shall be substantially round and shall meet the following
requirements:
(1) The difference between the maximum and minimum inside diameters at any cross section shall not exceed
1% of the nominal diameter at the cross section under
consideration. The diameters may be measured on the
inside or outside of the vessel. If measured on the outside,
the diameters shall be corrected for the plate thickness at
the cross section under consideration (see Fig. UG-80.2).
(2) When the cross section passes through an opening
or within 1 I.D. of the opening measured from the center of
the opening, the permissible difference in inside diameters
given above may be increased by 2% of the inside diameter
of the opening. When the cross section passes through any
other location normal to the axis of the vessel, including
head-to-shell junctions, the difference in diameters shall
not exceed 1%.
63
2010 SECTION VIII — DIVISION 1
For vessels with longitudinal lap joints, the permissible
difference in inside diameters may be increased by the
nominal plate thickness.
(b) External Pressure. The shell of a completed vessel
to operate under external pressure shall meet the following
requirements at any cross section:
(1) The out-of-roundness limitations prescribed in
(a)(1) and (a)(2) above.
(2) The maximum plus-or-minus deviation from the
true circular form, measured radially on the outside or
inside of the vessel, shall not exceed the maximum permissible deviation e obtained from Fig. UG-80.1. Use e p
1.0t or e p 0.2t, respectively, for points falling above or
below these curves. Measurements shall be made from a
segmental circular template having the design inside or
outside radius (depending upon where the measurements
are taken) and a chord length equal to twice the arc length
obtained from Fig. UG-29.2. The values of L and Do in
Figs. UG-29.2 and UG-80.1 shall be determined as follows:
(a) for cylinders, L and Do as defined in UG-28(b);
(b) for cones and conical sections, L and Do values
to be used in the figures are given below in terms of the
definitions given in UG-33(b). In all cases below,
(c) Where the shell at any cross section is made
of plates having different thicknesses, t is the nominal
thickness of the thinnest plate less corrosion allowance.
(4) For cones and conical sections, the value of t shall
be determined as in (3) above, except that t in (a), (b), and
(c) shall be replaced by te as defined in UG-33(b).
(5) The requirements of (b)(2) above shall be met in
any plane normal to the axis of revolution for cylinders
and cones and in the plane of any great circle for spheres.
For cones and conical sections, a check shall be made at
locations (1), (2), and (3) of (b)(2)(b) above and such other
locations as may be necessary to satisfy manufacturers and
inspectors that requirements are met.
(6) Measurements shall be taken on the surface of
the base metal and not on welds or other raised parts of
the material.
(7) The dimensions of a completed vessel may be
brought within the requirements of this paragraph by any
process which will not impair the strength of the material.
(8) Sharp bends and flat spots shall not be permitted
unless provision is made for them in the design.
(9) If the nominal thickness of plate used for a cylindrical vessel exceeds the minimum thickness required by
UG-28 for the external design pressure, and if such excess
thickness is not required for corrosion allowance or loadings causing compressive forces, the maximum permissible
deviation e determined for the nominal plate thickness used
may be increased by the ratio of factor B for the nominal
plate thickness used divided by factor B for the minimum
required plate thickness; and the chord length for measuring emax shall be determined by Do /t for the nominal plate
thickness used.
(10) An example illustrating the application of these
rules for a vessel under external pressure is given in L-4.
(c) Vessels and components fabricated of pipe or tube
under internal or external pressure may have permissible
variations in diameter (measured outside) in accordance
with those permitted under the specification covering its
manufacture.
Le p 0.5L (1 + Ds / DL )
(1) at the large diameter end,
L p Le
Do p D L
(2) at the small diameter end,
L p Le (DL / Ds )
Do p Ds
(3) at the midlength diameter,
L p Le [2DL / (DL + Ds )]
Do p 0.5 (DL + Ds )
(4) at any cross section having an outside diameter of Dx ,
UG-81
L p Le (DL / Dx )
TOLERANCE FOR FORMED HEADS
(a) The inner surface of a torispherical, toriconical,
hemispherical, or ellipsoidal head shall not deviate outside
of the specified shape by more than 11⁄4% of D nor inside
the specified shape by more than 5⁄8% of D, where D is the
nominal inside diameter of the vessel shell at point of
attachment. Such deviations shall be measured perpendicular to the specified shape and shall not be abrupt. The
knuckle radius shall not be less than that specified.
(b) Hemispherical heads or any spherical portion of a
torispherical or ellipsoidal head designed for external pressure shall, in addition to satisfying (a) above, meet the
Do p Dx
(c) for spheres, L is one-half of the outside diameter Do.
(3) For cylinders and spheres, the value of t shall be
determined as follows:
(a) For vessels with butt joints, t is the nominal
plate thickness less corrosion allowance.
(b) For vessels with longitudinal lap joints, t is the
nominal plate thickness and the permissible deviation is
t+e
64
2010 SECTION VIII — DIVISION 1
FIG. UG-84 SIMPLE BEAM IMPACT TEST
SPECIMENS (CHARPY TYPE TEST)
tolerances specified for spheres in UG-80(b) using a value
of 0.5 for L /Do.
(c) Measurements for determining the deviations specified in (a) above shall be taken from the surface of the
base metal and not from welds.
(d) The skirts of heads shall be sufficiently true to round
so that the difference between the maximum and minimum
inside diameters shall not exceed 1% of the nominal
diameter.
(e) When the skirt of any unstayed formed head is
machined to make a driving fit into or over a shell, the
thickness shall not be reduced to less than 90% of that
required for a blank head (see UW-13) or the thickness of
the shell at the point of attachment. When so machined,
the transition from the machined thickness to the original
thickness of the head shall not be abrupt but shall be tapered
for a distance of at least three times the difference between
the thicknesses.
UG-82
0.315 in. (8 mm)
2.165 in. (55 mm)
0.394 in.
(10 mm) [Note (1)]
0.010 in.
(0.25 mm) R
45
deg
NOTE:
(1) See UG-84(c) for thickness of reduced size specimen.
UG-84(b) Test Procedures
UG-84(b)(1) Impact test procedures and apparatus
shall conform to the applicable paragraphs of SA-370 or
ISO 148 (Parts 1, 2, and 3).
UG-84(b)(2) Unless permitted by Table UG-84.4,
impact test temperature shall not be warmer than the minimum design metal temperature [see UG-20(b)]. The test
temperature may be colder than the minimum specified in
the material specification of Section II.
UG-84(c) Test Specimens
UG-84(c)(1) Each set of impact test specimens shall
consist of three specimens.
UG-84(c)(2) The impact test specimens shall be of
the Charpy V-notch type and shall conform in all respects
to Fig. UG-84. The standard (10 mm ⴛ 10 mm) specimens,
when obtainable, shall be used for nominal thicknesses of
7
⁄16 in. (11 mm) or greater, except as otherwise permitted
in (c)(2)(a) below.
(a) For materials that normally have absorbed
energy in excess of 180 ft-lbf (240 J) when tested using
full size (10 mm ⴛ 10 mm) specimens at the specified
testing temperature, subsize (10 mm ⴛ 6.7 mm) specimens
may be used in lieu of full size specimens. However, when
this option is used, the acceptance value shall be 75 ftlbf (100 J) minimum for each specimen and the lateral
expansion in mils (mm) shall be reported.
UG-84(c)(3) For material from which full size (10
mm ⴛ 10 mm) specimens cannot be obtained, either due
to the material shape or thickness, the specimens shall
be either the largest possible standard subsize specimens
obtainable or specimens of full material nominal thickness
which may be machined to remove surface irregularities.
[The test temperature criteria of (c)(5)(b) below shall apply
for Table UCS-23 materials having a specified minimum
tensile strength less than 95,000 psi (655 MPa) when the
LUGS AND FITTING ATTACHMENTS
All lugs, brackets, saddle type nozzles, manhole frames,
reinforcement around openings, and other appurtenances
shall be formed and fitted to conform reasonably to the
curvature of the shell or surface to which they are attached.
(a) When pressure parts, such as saddle type nozzles,
manhole frames, and reinforcement around openings,
extend over pressure retaining welds, such welds shall be
ground flush for the portion of the weld to be covered.
(b) When nonpressure parts, such as lugs, brackets, and
support legs and saddles, extend over pressure retaining
welds, such welds shall be ground flush as described in
(a) above, or such parts shall be notched or coped to clear
those welds.
UG-83
HOLES FOR SCREW STAYS
Holes for screw stays shall be drilled full size or punched
not to exceed 1⁄4 in. (6 mm) less than full diameter of the
hole for plates over 5⁄16 in. (8 mm) in thickness and 1⁄8 in.
(3 mm) less than the full diameter of the hole for plates
not exceeding 5⁄16 in. (8 mm) in thickness, and then drilled
or reamed to the full diameter. The holes shall be tapped
fair and true with a full thread.
UG-84
CHARPY IMPACT TESTS
UG-84(a) General. Charpy V-notch impact tests in
accordance with the provisions of this paragraph shall be
made on weldments and all materials for shells, heads,
nozzles, and other vessel parts subject to stress due to
pressure for which impact tests are required by the rules
in Subsection C.
65
2010 SECTION VIII — DIVISION 1
width along the notch is less than 80% of the material
nominal thickness.] Alternatively, such material may be
reduced in thickness to produce the largest possible Charpy
subsize specimen. Toughness tests are not required where
the maximum obtainable Charpy specimen has a width
along the notch less than 0.099 in. (2.5 mm).
UG-84(c)(4)
(a) Except for materials produced and impact
tested in accordance with the requirements in the specifications listed in General Note (c) of Fig. UG-84.1, the applicable minimum energy requirement for all specimen sizes
for Table UCS-23 materials having a specified minimum
tensile strength less than 95,000 psi (655 MPa) shall be
that shown in Fig. UG-84.1, multiplied by the ratio of the
actual specimen width along the notch to the width of a
full-size (10 mm ⴛ 10 mm) specimen, except as otherwise
provided in (c)(2)(a) above.
(b) The applicable minimum lateral expansion
opposite the notch for all specimen sizes for Table UCS23 materials, having a specified minimum tensile strength
of 95,000 psi (655 MPa) or more, shall be as required
in UHT-6(a)(3) and UHT-6(a)(4). For UHT materials, all
requirements of UHT-6(a)(3) and UHT-6(a)(4) shall apply.
For Table UHA-23 materials, all requirements of UHA-51
shall apply.
UG-84(c)(5) For all Charpy impact tests the following test temperature criteria shall be observed:
(a) For Materials of Nominal Thickness Equal to
or Greater Than 0.394 in. (10 mm). Where the largest
obtainable Charpy V-notch specimen has a width along
the notch of at least 0.315 in. (8 mm), the Charpy test
using such a specimen shall be conducted at a temperature
not warmer than the minimum design metal temperature.31
Where the largest possible test specimen has a width along
the notch less than 0.315 in. (8 mm), the test shall be
conducted at a temperature lower than the minimum design
metal temperature 31 by the amount shown in Table
UG-84.2 for that specimen width. [This latter requirement
does not apply when the option of (c)(2)(a) above is used.]
(b) For Materials of Nominal Thickness Less Than
0.394 in. (10 mm). Where the largest obtainable Charpy
V-notch specimen has a width along the notch of at least
80% of the material nominal thickness, the Charpy test of
such a specimen shall be conducted at a temperature not
warmer than the minimum design metal temperature.31
Where the largest possible test specimen has a width
along the notch of less than 80% of the material nominal
thickness, the test, for Table UCS-23 materials having
specified minimum tensile strength of less than 95,000 psi
(655 MPa), shall be conducted at a temperature lower than
the minimum design metal temperature31 by an amount
equal to the difference (referring to Table UG-84.2)
between the temperature reduction corresponding to the
actual material thickness and the temperature reduction
corresponding to the Charpy specimen width actually
tested. [This latter requirement does not apply when the
option of (c)(2)(a) above is used.] For Table UCS-23 materials having a specified minimum tensile strength of
95,000 psi (655 MPa) and over, for Table UHT-23 materials, and for Table UHA-23 materials, the test shall be
conducted at a temperature not warmer than the minimum
design temperature.
UG-84(c)(6) When the average value of the three
specimens equals or exceeds the minimum value permitted
for a single specimen and the value for more than one
specimen is below the required average value, or when
the value for one specimen is below the minimum value
permitted for a single specimen, a retest of three additional
specimens shall be made. The value for each of these retest
specimens shall equal or exceed the required average value.
When an erratic result is caused by a defective specimen
or there is uncertainty in test procedure, a retest will be
allowed. When the option of (c)(2)(a) above is used for
the initial test and the acceptance value of 75 ft-lbf (100 J)
minimum is not attained, retest using full size (10 mm ⴛ
10 mm) specimens will be allowed.
UG-84(d) Impact Tests of Material
UG-84(d)(1) Reports or certificates of impact tests
by the material manufacturer will be acceptable evidence
that the material meets the requirements of this paragraph,
provided the specimens comply with UCS-85, UHT-5, or
UHT-81, as applicable.
UG-84(d)(2) The Manufacturer of the vessel may
have impact tests made to prove the suitability of a material
which the material manufacturer has not impact tested
provided the number of tests and the method of taking
the test specimens shall be as specified for the material
manufacturer (see UG-85).
UG-84(e) Procedural Requirements
UG-84(e)(1) Product Form Procedural Requirements. When no procedural requirements are listed in the
material specifications, impact testing of each form of
material shall comply with the applicable product form
procedural requirements of the specifications listed in
Table UG-84.3.
UG-84(e)(2) Small Parts. The Manufacturer of small
parts, either cast or forged, may certify a lot of not more
than 20 duplicate parts by reporting the results of one set
of impact specimens taken from one such part selected at
random, provided the same specification and heat of material and the same process of production, including heat
treatment, were used for all of the lot. When the part is
too small to provide the three specimens of at least minimum size shown in Fig. UG-84, no impact test need be
made.
31
Where applicable for Part UCS materials, the impact test temperature
may be adjusted in accordance with UG-84(b)(2) and Table UG-84.4.
66
2010 SECTION VIII — DIVISION 1
FIG. UG-84.1 CHARPY V-NOTCH IMPACT TEST REQUIREMENTS FOR FULL SIZE SPECIMENS FOR CARBON
AND LOW ALLOY STEELS, HAVING A SPECIFIED MINIMUM TENSILE STRENGTH OF LESS THAN 95 ksi,
LISTED IN TABLE UCS-23
50
Minimum specified
yield strength
40
Cv, ft-lb (average of three specimens)
65 ksi
55 ksi
30
50 ksi
45 ksi
20
38 ksi
10
0
0
0.394 0.5
1.0
1.5
2.0
2.5
3.0
Maximum Nominal Thickness of Material or Weld, in.
GENERAL NOTES:
(a) Interpolation between yield strengths shown is permitted.
(b) The minimum impact energy for one specimen shall not be less than 2⁄3 of the average energy required for three specimens. The average impact
energy value of the three specimens may be rounded to the nearest ft-lb.
(c) Material produced and impact tested in accordance with SA-320, SA-333, SA-334, SA-350, SA-352, SA-420, impact tested SA/AS 1548
(L impact designations), SA-437, SA-540 (except for materials produced under Table 2, Note 4 in SA-540), and SA-765 do not have to
satisfy these energy values. See UCS-66(g).
(d) For materials having a specified minimum tensile strength of 95 ksi or more, see UG-84(c)(4)(b).
67
2010 SECTION VIII — DIVISION 1
FIG. UG-84.1M CHARPY V-NOTCH IMPACT TEST REQUIREMENTS FOR FULL SIZE SPECIMENS FOR CARBON
AND LOW ALLOY STEELS, HAVING A SPECIFIED MINIMUM TENSILE STRENGTH OF LESS THAN 655 MPa,
LISTED IN TABLE UCS-23
60
Minimum specified
yield strength
450, <660 MPa
50
380 MPa
Cv, J (average of three specimens)
40
350 MPa
310 MPa
30
260 MPa
20
10
0
0
10
20
30
40
50
60
70
75
Maximum Nominal Thickness, mm
GENERAL NOTES:
(a) Interpolation between yield strengths shown is permitted.
(b) The minimum impact energy for one specimen shall not be less than 2⁄3 of the average energy required for three specimens. The average impact
energy value of the three specimens may be rounded to the nearest J.
(c) Material produced and impact tested in accordance with SA-320, SA-333, SA-334, SA-350, SA-352, SA-420, impact tested SA/AS 1548
(L impact designations), SA-437, SA-540 (except for materials produced under Table 2, Note 4 in SA-540), and SA-765 do not have to
satisfy these energy values. See UCS-66(g).
(d) For materials having a specified minimum tensile strength of 655 MPa or more, see UG-84(c)(4)(b).
68
2010 SECTION VIII — DIVISION 1
TABLE UG-84.2
CHARPY IMPACT TEST TEMPERATURE REDUCTION
BELOW MINIMUM DESIGN METAL TEMPERATURE
For Table UCS-23 Materials Having a Specified Minimum
Tensile Strength of Less Than 95,000 psi (655 MPa) When
the Subsize Charpy Impact Width Is Less Than 80% of the
Material Thickness
UG-84(e)(3) Small Vessels. For small vessels in conformance with U-1(j), one set of impact specimens of the
material may represent all vessels from the same heat of
material not in excess of 100 vessels or one heat-treatment
furnace batch, whichever is smaller.
UG-84(f) Impact Testing of Welds
UG-84(f)(1) For steel vessels of welded construction
the impact toughness of welds and heat affected zones of
procedure qualification test plates and vessel impact test
plates (production impact test plates) shall be determined
as required herein.
UG-84(f)(2) All test plates shall be subjected to heat
treatment, including cooling rates and aggregate time at
temperature or temperatures as established by the Manufacturer for use in actual manufacture. Heat treatment requirements of UG-85, UCS-85, UHT-81, and UHT-82 shall
apply to the test plates except that the provisions of
UCS-85(g) are not applicable to test plates for welds joining P-No. 3, Gr. Nos. 1 and 2 materials.
UG-84(g) Location, Orientation, Temperature, and
Values of Weld Impact Tests. All weld impact tests shall
comply with the following:
UG-84(g)(1) Each set of weld metal impact specimens shall be taken across the weld with the notch in the
weld metal. Each specimen shall be oriented so that the
notch is normal to the surface of the material and one face
of the specimen shall be within 1⁄16 in. (1.5 mm) of the
surface of the material.
UG-84(g)(2) Each set of heat affected zone impact
specimens shall be taken across the weld and of sufficient
length to locate, after etching, the notch in the heat affected
zone. The notch shall be cut approximately normal to the
material surface in such a manner as to include as much
heat affected zone material as possible in the resulting
fracture.
UG-84(g)(3) For welds made by a solid-state welding
process, such as for electric resistance welded (ERW) pipe,
the weld impact tests shall consist only of one set of three
specimens taken across the weld with the notch at the weld
centerline. Each specimen shall be oriented so that the
notch is normal to the surface of the material and one face
of the specimen shall be within 1⁄16 in. (1.5 mm) of the
surface of the material. The weld impact tests are not
required if the weld and the base metal have been: annealed,
normalized, normalized and tempered, double normalized
and tempered, or quenched and tempered.
UG-84(g)(4) The test temperature for welds and heat
affected zones shall not be higher than required for the
base materials.
UG-84(g)(5) Impact values shall be at least as high
as those required for the base materials.
UG-84(h) Impact Tests of Welding Procedure Qualifications
Actual Material Thickness [See UG-84(c)(5)(b)] of Charpy Impact
Specimen Width Along the Notch1
Thickness,
in. (mm)
Temperature Reduction,
°F (°C)
0.394
0.354
0.315
0.295
0.276
0.262
(Full-size standard bar) (10)
(9)
(8.00)
(3⁄4 size bar) (7.5)
(7)
(2⁄3 size bar) (6.7)
0
0
0
5
8
10
(0)
(0)
(0)
(3)
(4)
(6)
0.236
0.197
0.158
0.131
0.118
0.099
(6)
(1⁄2 size bar) (5.00)
(4)
(1⁄3 size bar) (3.3)
(3.00)
(1⁄4 size bar) (2.5)
15
20
30
35
40
50
(8)
(11)
(17)
(19)
(22)
(28)
NOTE:
(1) Straight line interpolation for intermediate values is permitted.
TABLE UG-84.3
SPECIFICATIONS FOR IMPACT TESTED MATERIALS
IN VARIOUS PRODUCT FORMS
Product Form
Spec. No.
Plates
Parts UCS and UHT
Part UHA
Pipe
Tubes
SA-20, S5
SA-480
SA-333
SA-334
Forgings
Castings
Bolting materials (and bars)
Piping fittings
SA-350
SA-352
SA-320
SA-420
TABLE UG-84.4
IMPACT TEST TEMPERATURE DIFFERENTIAL
Minimum Specified Yield
Strength, ksi (MPa)
Temperature Difference,
°F (°C)
[Note (1)]
≤40 (280)
≤55 (380)
>55 (380)
10 (6)
5 (3)
0 (0)
NOTE:
(1) Impact test temperature may be warmer than the minimum design
temperature by the amount shown.
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2010 SECTION VIII — DIVISION 1
UG-84(h)(1) General. For steel vessels of welded
construction, the impact toughness of the welds and heat
affected zones of the procedure qualification test plates
shall be determined in accordance with (g) above and the
following subparagraphs:
UG-84(h)(2) When Required. Welding procedure
impact tests shall be made when required by UCS-67,
UHT-82, or UHA-51. For vessels constructed to the rules
of Part UCS, the test plate material shall satisfy all of the
following requirements relative to the material to be used
in production:
(a) be of the same P-Number and Group Number;
(b) be in the same heat treated condition; and
(c) meet the minimum notch toughness requirements of UG-84(c)(4) for the thickest material of the range
of base material qualified by the procedure (see Fig.
UG-84.1).
If impact tests are required for the deposited weld metal,
but the base material is exempted from impact tests (as in
UHA-51), welding procedure test plates shall be made.
The test plate material shall be material of the same PNumber and Group Number used in the vessel. One set of
impact specimens shall be taken with the notch approximately centered in the weld metal and perpendicular to the
surface; the heat affected zone need not be impact tested.
When the welding procedure employed for production
welding is used for fillet welds only, it shall be qualified
by a groove weld qualification test. The qualification test
plate or pipe material shall meet the requirements of (a),
(b), and (c) above when impact testing is a requirement.
This welding procedure test qualification is in addition to
the requirements of Section IX, QW-202.2 for P-No. 11
materials.
UG-84(h)(3) Material Over 11⁄2 in. (38 mm) Thick.
When procedure tests are made on material over 11⁄2 in.
(38 mm) in thickness, three sets of impact specimens are
required. One set of heat affected zone specimens shall be
taken as described in (g)(2) above. Two sets of impact
specimens shall be taken from the weld with one set located
near [within 1⁄16 in. (1.5 mm)] the surface of one side of
the material and one set taken as near as practical midway
between the surface and the center of thickness of the
opposite side as described in (g) above.
UG-84(h)(4) Essential Variables. The additional
essential variables specified in Section IX, QW-250, for
impact testing are required.
UG-84(i) Vessel (Production) Impact Test Plates
UG-84(i)(1) General. In addition to the requirements
of (h) above, impact tests of welds and heat affected zones
shall be made in accordance with (g) above for each qualified welding procedure used on each vessel or group of
vessels as defined in (3) below. The vessel impact test
plate shall be from one of the heats of steel used for the
vessel or group of vessels. For Category A joints, the test
plate shall, where practicable, be welded as an extension
to the end of a production joint so that the test plate weldment will represent as nearly as practicable the quality and
type of welding in the vessel joint. For Category B joints
that are welded using a different welding procedure than
used on Category A joints, a test plate shall be welded under
the production welding conditions used for the vessel, using
the same type of equipment and at the same location and
using the same procedures as used for the joint, and it shall
be welded concurrently with the production welds or as
close to the start of production welding as practicable.
UG-84(i)(2) When Required. Vessel (production)
impact test plates shall be made for all joints for which
impact tests are required for the welding procedure by
UCS-67, UHT-82, or UHA-51 (except where production
test plates are specifically exempt by these paragraphs).
Test shall be made of the weld metal and /or heat affected
zone to the extent required by the procedure test (see
UCS-67 and UHA-51).
UG-84(i)(3) Number of Vessel Impact Test Plates
Required
(a) For each vessel, one test plate shall be made
for each welding procedure used for joints of Categories
A and B, unless the vessel is one of several as defined in
(b) or (c) below.
In addition, for Category A and B joints the following
requirements shall apply:
(1) If automatic or semiautomatic welding is
performed, a test plate shall be made in each position
employed in the vessel welding.
(2) If manual welding is also employed, a test
plate shall be made in the flat position only, except if
welding is to be performed in other positions a test plate
need be made in the vertical position only (where the major
portions of the layers of welds are deposited in the vertical
upward direction). The vertically welded test plate will
qualify the manual welding in all positions.
(b) For several vessels or parts of vessels, welded
within any 3 month period at one location, the plate thickness of which does not vary by more than 1⁄4 in. (6 mm),
or 25%, whichever is greater, and of the same specification
and grade of material, a test plate shall be made for each
400 ft (120 m) of joints welded by the same procedure.
(c) For small vessels not exceeding the volume
limitations defined in U-1(j) made from one heat of material
requiring impact tests, one welded test joint made from
the same heat of material and welded with the same electrode and the same welding procedure may represent one
lot of 100 vessels or less, or each heat treatment furnace
batch, whichever is smaller.
UG-84(j) Rejection. If the vessel test plate fails to meet
the impact requirements, the welds represented by the plate
shall be unacceptable. Reheat treatment and retesting or
retesting only are permitted.
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2010 SECTION VIII — DIVISION 1
UG-85
HEAT TREATMENT
within the permissible tolerances (UG-79, UG-80, UG-81,
UF-27, and UF-29);
(10) qualification of the welding and /or brazing procedures before they are used in fabrication [UG-84(h),
UW-28(b), and UB-31];
(11) qualification of welders and welding operators
and brazers before using the welders or brazers in production work (UW-29, UW-48, UB-32, and UB-43);
(12) examination of all parts prior to joining to make
certain they have been properly fitted for welding or brazing and that the surfaces to be joined have been cleaned and
the alignment tolerances are maintained (UW-31, UW-32,
UW-33, and UB-17);
(13) examination of parts as fabrication progresses,
for material marking (UG-94), that defects are not evident
(UG-95), and that dimensional geometries are maintained
(UG-96 and UF-30);
(14) provision of controls to assure that all required
heat treatments are performed (UW-2, UW-10, UG-85,
UF-31, and 10-11);
(15) provision of records of nondestructive testing
examinations performed on the vessel or vessel parts. This
shall include retaining the radiographic film if radiographic
examinations are performed (UW-51, UW-52, and 10-10);
(16) making the required hydrostatic or pneumatic
test and having the required inspection performed during
such test (UG-99, UG-100, UG-101, and UW-50);
(17) applying the required stamping and /or nameplate to the vessel and making certain it is applied to proper
vessel (UG-116, UG-118, and UG-119);
(18) preparing required Manufacturer’s Data Report
and having it certified by the Inspector (UG-120);
(19) providing for retention of radiographs (UW-51),
ultrasonic test reports (12-4), Manufacturer’s Data Reports
(UG-120), and other documents as required by this Division (10-13).
(c)(1) The Inspector shall make all inspections specifically required of him plus such other inspections as he
believes are necessary to enable him to certify that all
vessels which he authorizes to be stamped with the Code
Symbol have been designed and constructed in accordance
with the requirements of this Division. Some, but not all,
of the required inspections and verifications, which are
defined in the applicable rules, are summarized as follows:
(a) verifying that the Manufacturer has a valid Certificate of Authorization [UG-117(a)] and is working to a
Quality Control System [UG-117(e)];
(b) verifying that the applicable design calculations
are available [U-2(b), U-2(c), 10-5, and 10-15(d)];
(c) verifying that materials used in the construction
of the vessel comply with the requirements of UG-4
through UG-14 (UG-93);
(d) verifying that all welding and brazing procedures have been qualified (UW-28, UW-47, and UB-42);
When plate specification heat treatments are not performed by the material manufacturer, they shall be performed by, or be under the control of, the Manufacturer
who shall then place the letter “T” following the letter “G”
in the Mill plate marking (see SA-20) to indicate that the
heat treatments required by the material specification have
been performed. The Manufacturer shall also document in
accordance with UG-93(b) that the specified heat treatment
has been performed.
UCS-85, UHT-5(e), and UHT-81 provide requirements
for heat treatment of test specimens.
INSPECTION AND TESTS
UG-90
GENERAL
(a) The inspection and testing of pressure vessels to be
marked with the Code U Symbol and the testing of vessels
to be marked with the Code UM Symbol shall conform to
the general requirements for inspection and testing in the
following paragraphs and, in addition, to the specific
requirements for Inspection and Tests given in the applicable Parts of Subsections B and C.
(b) The Manufacturer has the responsibility of assuring
that the quality control, the detailed examinations, and
the tests required by this Division are performed. The
Manufacturer shall perform his specified duties. See UG-92
and 10-15. Some, but not all, of these responsibilities,
which are defined in the applicable rules, are summarized
as follows:
(1) the Certificate of Authorization from the ASME
Boiler and Pressure Vessel Committee authorizing the
Manufacturer to fabricate the class of vessel being constructed [UG-117(a)];
(2) the drawings and design calculations for the vessel or part [10-5 and 10-15(d)];
(3) identification for all material used in the fabrication of the vessel or part (UG-93);
(4) securing Partial Data Reports [UG-120(c)];
(5) access for the Inspector in accordance with UG-92
and 10-15;
(6) examination of all materials before fabrication to
make certain they have the required thickness, to detect
defects [UG-93(d)], to make certain the materials are permitted by this Division (UG-4), and that traceability
(UG-77) to the material identification (UG-93) has been
maintained;
(7) documentation of impact tests when such tests are
required (UF-5, UCS-66, UHA-51, UHT-6, and ULT-5);
(8) concurrence of the Inspector prior to any base
metal repairs (UG-78 and UF-37);
(9) examination of the shell and head sections to confirm they have been properly formed to the specified shapes
71
2010 SECTION VIII — DIVISION 1
(e) verifying that all welders, welding operators,
brazers, and brazing operators have been qualified (UW-29,
UW-48, and UB-43);
(f) verifying that the heat treatments, including
PWHT, have been performed (UG-85, UW-10, UW-40,
UW-49, and UF-52);
(g) verifying that material imperfections repaired
by welding were acceptably repaired [UG-78,
UW-52(d)(2)(c), UF-37, and UF-47(c)];
(h) verifying that weld defects were acceptably
repaired [UW-51(c) and UW-52(c)];
(i) verifying that required nondestructive examinations, impact tests, and other tests have been performed
and that the results are acceptable (UG-84, UG-93, UW-50,
UW-51, UW-52, and UB-44);
(j) making a visual inspection of vessel to confirm
that the material identification numbers have been properly
transferred (UG-77 and UG-94);
(k) making a visual inspection of the vessel to confirm that there are no material or dimensional defects
(UG-95, UG-96, and UG-97);
(l) performing internal and external inspections
and witnessing the hydrostatic or pneumatic tests (UG-96,
UG-97, UG-99, UG-100, and UG-101);
(m) verifying that the required marking is provided
(UG-115) and that any nameplate has been attached to the
proper vessel;
(n) signing the Certificate of Inspection on the
Manufacturer’s Data Report when the vessel, to the best
of his knowledge and belief, is in compliance with all the
provisions of this Division.
(2) When mass production of pressure vessels makes
it impracticable for the Inspector to personally perform
each of his required duties,32 the Manufacturer, in collaboration with the Inspector, shall prepare an inspection and
quality control procedure setting forth, in complete detail,
the method by which the requirements32 of this Division
will be maintained. This procedure shall be developed,
accepted, and implemented in accordance with Mandatory
Appendix 35.
UG-91
inspection organization of a state or municipality of the
United States, a Canadian province, or an insurance company authorized to write boiler and pressure vessel insurance, except that
(2) inspections may be by the regularly employed
user’s Inspector in the case of a User-Manufacturer which
manufactures pressure vessels exclusively for its own use
and not for resale [see UG-116(a)(1)].
Except as permitted in (2) above, the Inspector shall not
be in the employ of the Manufacturer. All Inspectors shall
have been qualified by a written examination under the
rules of any state of the United States or province of Canada
which has adopted the Code.
(b) In addition to the duties specified, the Inspector has
the duty to monitor the Manufacturer’s Quality Control
System as required in Appendix 10.
UG-92
ACCESS FOR INSPECTOR
The Manufacturer of the vessel shall arrange for the
Inspector to have free access to such parts of all plants as
are concerned with the supply or manufacture of materials
for the vessel, when so requested. The Inspector shall be
permitted free access, at all times while work on the vessel
is being performed, to all parts of the Manufacturer’s shop
that concern the construction of the vessel and to the site
of field erected vessels during the period of assembly and
testing of the vessel. The Manufacturer shall keep the
Inspector informed of the progress of the work and shall
notify him reasonably in advance when vessels will be
ready for any required tests or inspections.
UG-93
INSPECTION OF MATERIALS
(a) Except as otherwise provided in UG-4(b), UG-10,
UG-11, or UG-15, requirements for acceptance of materials
furnished by the material manufacturer or material supplier
in complete compliance with a material specification of
Section II shall be as follows.
(1) For plates,2 the vessel Manufacturer shall obtain
the material test report or certificate of compliance as provided for in the material specification and the Inspector
shall examine the Material Test Report or certificate of
compliance and shall determine that it represents the material and meets the requirements of the material specification.
(2) For all other product forms, the material shall be
accepted as complying with the material specification if
the material specification provides for the marking of each
piece with the specification designation, including the
grade, type, and class if applicable, and each piece is so
marked.
(3) If the material specification does not provide for
the marking of each piece as indicated in (a)(2) above, the
THE INSPECTOR
(a) All references to Inspectors throughout this Division
mean the Authorized Inspector as defined in this paragraph.
All inspections required by this Division of Section VIII
shall be:
(1) by an Inspector regularly employed by an ASME
accredited Authorized Inspection Agency, 33 i.e., the
32
See UG-90(b) and UG-90(c)(1) for summaries of the responsibilities
of the Manufacturer and the duties of the Inspector.
33
Whenever Authorized Inspection Agency or AIA is used in this Code,
it shall mean an Authorized Inspection Agency accredited by ASME in
accordance with the requirements in the latest edition of ASME QAI-1.
72
2010 SECTION VIII — DIVISION 1
material shall be accepted as complying with the material
specification provided the following requirements are met.
(a) Each bundle, lift, or shipping container is
marked with the specification designation, including the
grade, type, and class if applicable by the material manufacturer or supplier.
(b) The handling and storage of the material by
the vessel Manufacturer shall be documented in his Quality
Control System such that the Inspector can determine that
it is the material identified in (a)(3)(a) above. Traceability
to specific lot, order, or heat is not required. Traceability
is required only to material specification and grade and
type and class, if applicable.
(4) For pipe or tube where the length is not adequate
for the complete marking in accordance with the material
specification or not provided in accordance with (a)(3)
above, the material shall be acceptable as complying with
the material specification provided the following are met:
(a) a coded marking is applied to each piece of
pipe or tube by the material manufacturer or material supplier; and
(b) the coded marking applied by the material manufacturer or material supplier is traceable to the specification designation, including the grade, type, and class if
applicable.
(b) Except as otherwise provided in UG-4(b), UG-10,
UG-11, or UG-15, when some requirements of a material
specification of Section II have been completed by other
than the material manufacturer [see UG-84(d) and UG-85],
then the vessel Manufacturer shall obtain supplementary
material test reports or certificates of compliance and the
Inspector shall examine these documents and shall determine that they represent the material and meet the requirements of the material specification.
(c) When requirements or provisions of this Division
applicable to materials exceed or supplement the requirements of the material specification of Section II (see
UG-24, UG-84, and UG-85), then the vessel Manufacturer
shall obtain supplementary material test reports or certificates of compliance and the Inspector shall examine these
documents and shall determine that they represent the material and meet the requirements or provisions of this
Division.
(d) All materials to be used in constructing a pressure
vessel shall be examined before fabrication for the purpose
of detecting, as far as possible, imperfections which would
affect the safety of the vessel.
(1) Particular attention should be given to cut edges
and other parts of rolled plate which would disclose the
existence of serious laminations, shearing cracks, and other
imperfections.
(2) All materials that are to be tested in accordance
with the requirements of UG-84 shall be inspected for
surface cracks.
(3) When a pressure part is to be welded to a flat
plate thicker than 1⁄2 in. (13 mm) to form a corner joint
under the provision of UW-13(e), the weld joint preparation
in the flat plate shall be examined before welding as specified in (d)(4) below by either the magnetic particle or liquid
penetrant methods. After welding, both the peripheral edge
of the flat plate and any remaining exposed surface of the
weld joint preparation shall be reexamined by the magnetic
particle or liquid penetrant methods as specified in (d)(4)
below. When the plate is nonmagnetic, only the liquid
penetrant method shall be used. The requirements of this
paragraph shall not apply to those joints when 80% or
more of the pressure load is carried by tubes, stays, or
braces.
(4) For Fig. UW-13.2 the weld joint preparation and
the peripheral edges of flat plate forming a corner joint
shall be examined as follows:
(a) the weld edge preparation of typical weld joint
preparations in the flat plate as shown in sketches (b), (c),
(d), (f), and (n);
(b) the outside peripheral edge of the flat plate after
welding as shown in sketches (a), (b), (c), and (d);
(c) the outside peripheral edge of the flat plate after
welding, as shown in sketches (e), (f), and (g) if the distance
from the edge of the completed weld to the peripheral edge
of the flat plate is less than the thickness of the flat plate
such as defined in UG-34(b);
(d) the inside peripheral surface of the flat plate
after welding as shown in sketches (m) and (n);
(e) no examination is required on the flat plate as
shown in sketches (h), (i), (j), (k), and (l).
(e) The Inspector shall assure himself that the thickness
and other dimensions of material comply with the requirements of this Division.
(f) The Inspector shall satisfy himself that the inspection
and marking requirements of UG-24 have been complied
with for those castings assigned a casting quality factor
exceeding 80%.
UG-94
MARKING ON MATERIALS
The Inspector shall inspect materials used in the construction to see that they bear the identification required by
the applicable material specification, except as otherwise
provided in UG-4(b), UG-10, UG-11, UG-15, or UG-93.
Should the identifying marks be obliterated or the material
be divided into two or more parts, the marks shall be
properly transferred by the Manufacturer as provided in
UG-77(a). See UG-85.
UG-95
EXAMINATION OF SURFACES
DURING FABRICATION
As fabrication progresses, all materials used in the construction shall be examined for imperfections that have
73
2010 SECTION VIII — DIVISION 1
been uncovered during fabrication as well as to determine
that the work has been done properly.
UG-96
the rules and formulas in this Division, together with the
effect of any combination of loadings listed in UG-22
which are likely to occur, for the designated coincident
temperature, excluding any metal thickness specified as
corrosion allowance. See UG-25.
UG-98(c) Maximum allowable working pressure may
be determined for more than one designated operating temperature, using for each temperature the applicable allowable stress value.
DIMENSIONAL CHECK OF
COMPONENT PARTS
(a) The Manufacturer shall examine the pressure
retaining parts to make certain they conform to the prescribed shape and meet the thickness requirements after
forming. The Manufacturer of the vessel shall furnish accurately formed templates as required by the Inspector for
verification. See UG-80.
(b) Before attaching nozzles, manhole frames, nozzle
reinforcement and other appurtenances to the inside or
outside of the vessel they shall be examined to make certain
they properly fit the vessel curvature. See UG-82.
(c) The Inspector shall satisfy himself that the above
dimensional requirements have been met. This shall
include making such dimensional measurements as he considers necessary.
UG-97
UG-99
(a) A hydrostatic test shall be conducted on all vessels after:
(1) all fabrication has been completed, except for
operations which could not be performed prior to the test
such as weld end preparation [see U-1(e)(1)(a)], cosmetic
grinding on the base material which does not affect the
required thickness; and
(2) all examinations have been performed, except
those required after the test.
The completed vessels, except those tested in accordance
with the requirements of UG-100 and UG-101, shall have
satisfactorily passed the hydrostatic test prescribed in this
paragraph.
(b) Except as otherwise permitted in (a) above and 274, vessels designed for internal pressure shall be subjected
to a hydrostatic test pressure that at every point in the
vessel is at least equal to 1.3 times the maximum allowable
working pressure34 multiplied by the lowest stress ratio
(LSR) for the materials of which the vessel is constructed.
The stress ratio for each material is the stress value S
at its test temperature to the stress value S at its design
temperature (see UG-21). Bolting shall not be included in
the determination of the LSR, except when 1.3 times the
LSR multiplied by the allowable stress of the bolt at its
design temperature exceeds 90% of the bolt material specified minimum yield strength at the test temperature. All
loadings that may exist during this test shall be given
consideration.
(c) A hydrostatic test based on a calculated pressure
may be used by agreement between the user and the Manufacturer. The hydrostatic test pressure at the top of the
vessel shall be the minimum of the test pressures calculated
by multiplying the basis for calculated test pressure as
defined in 3-2 for each pressure element by 1.3 and reducing this value by the hydrostatic head on that element.
When this pressure is used, the Inspector shall reserve the
right to require the Manufacturer or the designer to furnish
the calculations used for determining the hydrostatic test
pressure for any part of the vessel.
INSPECTION DURING
FABRICATION
(a) When conditions permit entry into the vessel, as
complete an examination as possible shall be made before
final closure.
(b) The Inspector shall make an external inspection of
the completed vessel at the time of the final hydrostatic
test or pneumatic test.
(c) All welds, including the nozzle welds, of homogeneously lead-lined vessels shall be visually inspected on the
inside prior to application of lining. A visual examination of
the lining shall be made after completion to assure that
there are no imperfections which might impair the integrity
of the lining and subject the vessel to corrosion effects.
UG-98
STANDARD HYDROSTATIC TEST
MAXIMUM ALLOWABLE WORKING
PRESSURE
UG-98(a) The maximum allowable working pressure
for a vessel is the maximum pressure permissible at the
top of the vessel in its normal operating position at the
designated coincident temperature specified for that pressure. It is the least of the values found for maximum
allowable working pressure for any of the essential parts
of the vessel by the principles given in (b) below, and
adjusted for any difference in static head that may exist
between the part considered and the top of the vessel. (See
3-2.)
UG-98(b) The maximum allowable working pressure
for a vessel part is the maximum internal or external pressure, including the static head thereon, as determined by
34
The maximum allowable working pressure may be assumed to be
the same as the design pressure when calculations are not made to determine the maximum allowable working pressure.
74
(10)
2010 SECTION VIII — DIVISION 1
(d) The requirements of (b) above represent the minimum standard hydrostatic test pressure required by this
Division. The requirements of (c) above represent a special
test based on calculations. Any intermediate value of pressure may be used. This Division does not specify an upper
limit for hydrostatic test pressure. However, if the hydrostatic test pressure is allowed to exceed, either intentionally
or accidentally, the value determined as prescribed in (c)
above to the degree that the vessel is subjected to visible
permanent distortion, the Inspector shall reserve the right
to reject the vessel.
(e) Combination units [see UG-19(a) and UG-21] shall
be tested by one of the following methods.
(1) Pressure chambers of combination units that have
been designed to operate independently shall be hydrostatically tested as separate vessels, that is, each chamber shall
be tested without pressure in the adjacent chamber. If the
common elements of a combination unit are designed for
a larger differential pressure than the higher maximum
allowable working pressure to be marked on the adjacent
chambers, the hydrostatic test shall subject the common
elements to at least their design differential pressure, corrected for temperature as in (b) above, as well as meet the
requirements of (b) or (c) above for each independent
chamber.
(2) When pressure chambers of combination units
have their common elements designed for the maximum
differential pressure that can possibly occur during startup,
operation, and shutdown, and the differential pressure is
less than the higher pressure in the adjacent chambers, the
common elements shall be subjected to a hydrostatic test
pressure of at least 1.3 times the differential pressure to
be marked on the unit, corrected for temperature as in
UG-99(b).
Following the test of the common elements and their
inspection as required by (g) below, the adjacent chambers
shall be hydrostatically tested simultaneously [see (b) or
(c) above]. Care must be taken to limit the differential
pressure between the chambers to the pressure used when
testing the common elements.
The vessel stamping and the vessel Data Report must
describe the common elements and their limiting differential pressure. See UG-116(j) and UG-120(b).
(f) Single-wall vessels designed for a vacuum or partial
vacuum only, and chambers of multichamber vessels
designed for a vacuum or partial vacuum only, shall be
subjected to an internal hydrostatic test or when a hydrostatic test is not practicable, to a pneumatic test in accordance with the provisions of UG-100. Either type of test
shall be made at a pressure not less than 1.3 times the
difference between normal atmospheric pressure and the
minimum design internal absolute pressure.
(g) Following the application of the hydrostatic test
pressure, an inspection shall be made of all joints and
connections. This inspection shall be made at a pressure
not less than the test pressure divided by 1.3. Except for
leakage that might occur at temporary test closures for
those openings intended for welded connections, leakage
is not allowed at the time of the required visual inspection.
Leakage from temporary seals shall be directed away so
as to avoid masking leaks from other joints.
The visual inspection of joints and connections for leaks
at the test pressure divided by 1.3 may be waived provided:
(1) a suitable gas leak test is applied;
(2) substitution of the gas leak test is by agreement
reached between Manufacturer and Inspector;
(3) all welded seams which will be hidden by assembly be given a visual examination for workmanship prior
to assembly;
(4) the vessel will not contain a “lethal” substance.
(h) Any nonhazardous liquid at any temperature may
be used for the hydrostatic test if below its boiling point.
Combustible liquids having a flash point less than 110°F
(43°C), such as petroleum distillates, may be used only
for near atmospheric temperature tests. It is recommended
that the metal temperature during hydrostatic test be maintained at least 30°F (17°C) above the minimum design
metal temperature, but need not exceed 120°F (48°C), to
minimize the risk of brittle fracture. [See UG-20 and General Note (6) to Fig. UCS-66.2.] The test pressure shall
not be applied until the vessel and its contents are at about
the same temperature. If the test temperature exceeds 120°F
(48°C), it is recommended that inspection of the vessel
required by (g) above be delayed until the temperature is
reduced to 120°F (48°C) or less.
CAUTION: A small liquid relief valve set to 11⁄3 times the test pressure
is recommended for the pressure test system, in case a vessel, while under
test, is likely to be warmed up materially with personnel absent.
(i) Vents shall be provided at all high points of the
vessel in the position in which it is to be tested to purge
possible air pockets while the vessel is filling.
(j) Before applying pressure, the test equipment shall
be examined to see that it is tight and that all low-pressure
filling lines and other appurtenances that should not be
subjected to the test pressure have been disconnected.
(k) Vessels, except for those in lethal service, may be
painted or otherwise coated either internally or externally,
and may be lined internally, prior to the pressure test.
However, the user is cautioned that such painting /
coating /lining may mask leaks that would otherwise have
been detected during the pressure test.
75
2010 SECTION VIII — DIVISION 1
(10)
UG-100
PNEUMATIC TEST35 (SEE UW-50)
connections, leakage is not allowed at the time of the
required visual inspection. Leakage from temporary seals
shall be directed away so as to avoid masking leaks from
other joints.
The visual inspection of the vessel at the required test
pressure divided by 1.1 may be waived provided:
(1) a suitable gas leak test is applied;
(2) substitution of the gas leak test is by agreement
reached between Manufacturer and Inspector;
(3) all welded seams which will be hidden by assembly be given a visual examination for workmanship prior
to assembly;
(4) the vessel will not contain a “lethal” substance.
(e) Vessels, except for those in lethal service, may be
painted or otherwise coated either internally or externally,
and may be lined internally, prior to the pressure test.
However, the user is cautioned that such painting /
coating /lining may mask leaks that would otherwise have
been detected during the pressure test.
(a) Subject to the provisions of UG-99(a)(1) and (a)(2),
a pneumatic test prescribed in this paragraph may be used
in lieu of the standard hydrostatic test prescribed in UG-99
for vessels:
(1) that are so designed and /or supported that they
cannot safely be filled with water;
(2) not readily dried, that are to be used in services
where traces of the testing liquid cannot be tolerated and
the parts of which have, where possible, been previously
tested by hydrostatic pressure to the pressure required in
UG-99.
(b) Except for enameled vessels, for which the pneumatic test shall be at least equal to, but not exceed, the
maximum allowable working pressure to be marked on the
vessel, the pneumatic test pressure at every point in the
vessel shall be at least equal to 1.1 times the maximum
allowable working pressure34 multiplied by the lowest
stress ratio (LSR) for the materials of which the vessel is
constructed. The stress ratio for each material is the stress
value S at its test temperature to the stress value S at
its design temperature (see UG-21). Bolting shall not be
included in the determination of the LSR, except when 1.1
times the LSR multiplied by the allowable stress of the
bolt at its design temperature exceeds 90% of the bolt
material specified minimum yield strength at the test temperature. All loadings that may exist during this test shall
be given consideration. In no case shall the pneumatic test
pressure exceed 1.1 times the basis for the calculated test
pressure as defined in 3-2.
(c) The metal temperature during pneumatic test shall
be maintained at least 30°F (17°C) above the minimum
design metal temperature to minimize the risk of brittle
fracture. [See UG-20 and General Note (6) to Fig.
UCS-66.2.]
(d) The pressure in the vessel shall be gradually
increased to not more than one-half of the test pressure.
Thereafter, the test pressure shall be increased in steps
of approximately one-tenth of the test pressure until the
required test pressure has been reached. Then the pressure
shall be reduced to a value equal to the test pressure divided
by 1.1 and held for a sufficient time to permit inspection
of the vessel. Except for leakage that might occur at temporary test closures for those openings intended for welded
UG-101
PROOF TESTS TO ESTABLISH
MAXIMUM ALLOWABLE WORKING
PRESSURE
UG-101(a) General
UG-101(a)(1) The maximum allowable working
pressure for vessels or vessel parts for which the strength
cannot be computed with a satisfactory assurance of accuracy (see U-2) shall be established in accordance with
the requirements of this paragraph, using one of the test
procedures applicable to the type of loading and to the
material used in construction. Production vessels or vessel
parts that utilize the results of a proof test shall comply
with all applicable construction rules of the current edition
and applicable addenda of this Division.
UG-101(a)(1)(a) Consideration of the use of
proof-tested construction specifications based on past editions of this Division and documented in the original Proof
Test Report requires that the Manufacturer determine
whether or not there have been subsequent revisions to
this Division that apply and must be evaluated. This evaluation may void the Division acceptability of establishing
the vessel MAWP by proof testing (e.g., UCS-66, Part
UHX, Appendix 13, etc.). However, if applicable revisions
are found, and it is judged that a new proof test is not
required, the Manufacturer, using Duplicate and Similar
Parts rules in UG-101(d) as guidelines, shall prepare a
Supplement to the original Proof Test Report documenting
any changes to the construction requirements and to the
Manufacturer’s Data Report. It is noted that
35
In some cases it is desirable to test vessels when partly filled with
liquids. For such vessels a combined hydrostatic and pneumatic test may
be used as an alternative to the pneumatic test of this paragraph, provided
the liquid level is set so that the maximum stress including the stress
produced by pneumatic pressure at any point in the vessel (usually near
the bottom) or in the support attachments, does not exceed 1.3 times the
allowable stress value of the material multiplied by the applicable joint
efficiency. After setting the liquid level to meet this condition, the test
is conducted as prescribed in (b) and (c) above.
Air or gas is hazardous when used as a testing medium. It is therefore
recommended that special precautions be taken when air or gas is used
for test purposes.
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2010 SECTION VIII — DIVISION 1
UG-101(a)(1)(a)(1) The production vessel
material need not be identical with that used for the original
proof tested vessel, but material equivalence must be confirmed and documented.
UG-101(a)(1)(a)(2) The MDMT established by
current Division rules may be different from that originally
assigned but must be suitable for the nameplate MDMT
marking coincident with the established MAWP.
UG-101(a)(1)(a)(3) The Supplement to the original Proof Test Report shall be made available to the Inspector prior to the start of construction.
UG-101(a)(2) Provision is made in these rules for
two types of tests to determine the internal maximum
allowable working pressure:
(a) tests based on yielding of the part to be tested.
These tests are limited to materials with a ratio of minimum
specified yield to minimum specified ultimate strength of
0.625 or less.
(b) tests based on bursting of the part.
UG-101(a)(3) Safety of testing personnel should be
given serious consideration when conducting proof tests,
and particular care should be taken during bursting tests
in (m) below.
UG-101(a)(4) The Code recognizes that Manufacturers may maintain control of proof test reports under different ownerships than existed during the original application
of the proof test. When a Manufacturer is acquired by a
new owner(s), the proof test reports may be used by the new
owner(s) without retesting, provided all of the following are
met:
(a) the new owner(s) takes responsibility for the
proof tests;
(b) the Proof Test Reports reflect the name of the
new owner(s);
(c) the Proof Test Reports indicate the actual test
was performed by the former Manufacturer;
(d) the Proof Test Report(s) is acceptable to the
Inspector of the new owner(s) as indicated by his/her signature on the Manufacturer’s report of the test.
UG-101(b) The tests in these paragraphs may be used
only for the purpose of establishing the maximum allowable working pressure of those elements or component
parts for which the thickness cannot be determined by
means of the design rules given in this Division. The maximum allowable working pressure of all other elements or
component parts shall not be greater than that determined
by means of the applicable design rules.
Tests to establish the maximum allowable working pressure of vessels, or vessel parts, shall be witnessed by and
be acceptable to the Inspector, as indicated by his signature
on the Manufacturer’s Proof Test Report. The report shall
include sufficient detail to describe the test, the instrumentation and the methods of calibration used, and the results
obtained. The report shall be made available to the Inspector for each application [see U-2(b) and UG-90(b)(2)].
UG-101(c) The vessel or vessel part for which the maximum allowable working pressure is to be established shall
not previously have been subjected to a pressure greater
than 1.3 times the desired or anticipated maximum allowable working pressure, adjusted for operating temperature
as provided in (k) below.
UG-101(d) Duplicate and Similar Parts. When the
maximum allowable working pressure of a vessel or vessel
part has been established by a proof test, duplicate parts,
or geometrically similar parts, that meet all of the requirements in (d)(1) or (d)(2) below, need not be proof tested
but shall be given a hydrostatic pressure test in accordance
with UG-99, or a pneumatic pressure test in accordance
with UG-100, except as otherwise provided in UCI-101,
and UCD-101.
UG-101(d)(1) Duplicate Parts. All of the following
requirements shall be met in order to qualify a part as a
duplicate of the part that had been proof tested:
(a) same basic design configuration and type of
construction;
(b) the material of the duplicate part is either:
(1) the same material specifications:
(a) alloy;
(b) grade, class;
(c) type, form;
(d) heat treatment; or
(2) the same or closely similar material when
only the material specification, the alloy, grade, or form
is different, provided the material meets the following additional requirements:
(a) has allowable stress in tension equal to or
greater than the material used in the proof tested part at
the test temperature [see (k) below];
(b) has the same P-Number (Section IX);
(c) for carbon or low alloy steels (Part UCS),
has the same or tougher material grouping in UCS-66, Fig.
UCS-66, and Notes;
(c) the nominal dimensions, diameter, or width and
height, of the duplicate parts shall be the same, and the
corresponding nominal thicknesses shall be the same as
those used in the proof test. The length shall not be longer
than that proof tested.
(d) heat treatment shall be the same as performed
on the original part that was tested;
(e) the MAWP shall be calculated according to (e)
below;
(f) when there are permissible deviations from the
original part that was proof tested, a supplement to the
original Proof Test Report shall be prepared that states and
evaluates each deviation.
UG-101(d)(2) Geometrically Similar Parts. The
maximum allowable working pressure for geometrically
77
2010 SECTION VIII — DIVISION 1
similar parts may be established by a series of proof tests
that uniformly cover the complete range of sizes, pressure,
or other variables by interpolation from smooth curves
plotted from the results of the tests.36
(a) Sufficient tests shall be performed to provide
at least five data points that are at increments that are
within 20% to 30% of the range covered.
(b) The curves shall be based on the lower bound
of the test data.
(c) Extrapolation is not permitted.
UG-101(e) Proof test methods UG-101(l), (m), (n), and
(o) below establish a pressure at which the test is terminated. The results of the test are recorded in a Proof Test
Report according to UG-101(b).
UG-101(e)(1) The MAWP for the first duplicate part,
as defined in UG-101(d), to be put into service, shall be
calculated according to the equations given in the proof
test method applied.
The requirements for NDE are given in UG-24 and
UW-12. Other requirements are based on thickness or
material. These apply to parts which are to be put into
service. It is not necessary to examine the part actually
tested.
UG-101(e)(2) For subsequent duplicate parts, the
MAWP may be recalculated for a different extent of NDE
in a supplement to the original Proof Test Report.
UG-101(e)(3) The effect of the location of a weld
joint may be evaluated and included in the Proof Test
Report.
UG-101(f) A retest shall be allowed on a duplicate vessel or vessel part if errors or irregularities are obvious in
the test results.
UG-101(g) In tests for determination of governing
stresses, sufficient locations on the vessel shall be investigated to ensure that measurements are taken at the most
critical areas. As a check that the measurements are being
taken on the most critical areas, the Inspector may require
a brittle coating to be applied on all areas of probable high
stress concentrations in the test procedures given in (n)
and (o) below. The surfaces shall be suitably cleaned before
the coating is applied in order to obtain satisfactory adhesion. The technique shall be suited to the coating material.
part shall be increased gradually until approximately onehalf the anticipated working pressure is reached. Thereafter, the test pressure shall be increased in steps of approximately one-tenth or less of the anticipated maximum
allowable working pressure until the pressure required by
the test procedure is reached. The pressure shall be held
stationary at the end of each increment for a sufficient time
to allow the observations required by the test procedure to
be made, and shall be released to zero to permit determination of any permanent strain after any pressure increment
that indicates an increase in strain or displacement over
the previous equal pressure increment.
UG-101(i) Corrosion Allowance. The test procedures
in this paragraph give the maximum allowable working
pressure for the thickness of material tested. The thickness
of the pressure vessel that is to be proof tested should be
the corroded thickness. When this is not practical and when
the thickness as tested includes extra thickness as provided
in UG-25, the maximum allowable working pressure at
which the vessel shall be permitted to operate shall be
determined by multiplying the maximum allowable working pressure obtained from the test by the ratio
(t − c ) n / t n
where
c p allowance added for corrosion, erosion, and
abrasion
n p 1 for curved surfaces such as parts of cylinders,
spheres, cones with angle ≤ 60 deg; for stayed
surfaces similar to those described in UW-19(b)
and (c); and parts whose stress due to bending is
≤67% of the total stress
p 2 for flat or nearly flat surfaces, such as flat sides,
flanges, or cones with angle > 60 deg (except
for stayed surfaces noted above) unless it can be
shown that the stress due to bending at the limiting
location is <67% of the total stress
t p nominal thickness of the material at the weakest point
UG-101(j) Determination of Yield Strength and Tensile
Strength
UG-101(j)(1) For proof tests based on yielding, (l),
(n), or (o) below, the yield strength (or yield point for
those materials which exhibit that type of yield behavior
indicated by a “sharp-kneed” portion of the stress-strain
diagram) of the material in the part tested shall be determined in accordance with the method prescribed in the
applicable material specification. For proof tests based on
bursting [see (m) below], the tensile strength instead of
the yield strength of the material in the part tested shall
be similarly determined.
UG-101(j)(2) Yield or tensile strength so determined
shall be the average from three or four specimens cut from
NOTE: Strains should be measured as they apply to membrane stresses
and to bending stresses within the range covered by UG-23(c).
UG-101(h) Application of Pressure. In the procedures
given in (l), (n), and (o) below, the Displacement Measurement Test, the hydrostatic pressure in the vessel or vessel
36
Examples of the use of modeling techniques are found in
UG-127(a)(1)(b)(2) and UG-131(d)(2)(b), or refer to textbooks on the
subject.
78
2010 SECTION VIII — DIVISION 1
the part tested after the test is completed. The specimens
shall be cut from a location where the stress during the
test has not exceeded the yield strength. The specimens
shall not be flame cut because this might affect the strength
of the material. If yield or tensile strength is not determined
by test specimens from the pressure part tested, alternative
methods are given in (l), (m), (n), and (o) below for evaluation of proof test results to establish the maximum allowable working pressure.
UG-101(j)(3) When excess stock from the same piece
of wrought material is available and has been given the
same stress relieving heat treatment as the pressure part,
the test specimens may be cut from this excess stock. The
specimen shall not be removed by flame cutting or any
other method involving sufficient heat to affect the properties of the specimen. When the sheet material is used, test
specimens obtained from another piece cut from the same
coil of sheet used in the proof tested component meet the
requirements of this paragraph.
UG-101(k) Maximum Allowable Working Pressure at
Higher Temperatures. The maximum allowable working
pressure for vessels and vessel parts that are to operate at
temperatures at which the allowable stress value of the
material is less than at the test temperature shall be determined by the following formula:
P0 p P t
UG-101(l)(2) The maximum allowable working pressure P in pounds per square inch (MPa) at test temperature
for parts tested under this paragraph shall be computed by
one of the following formulas.
(a) If the average yield strength is determined in
accordance with (j) above,
P p 0.5H
Sy
Sy avg
(b) To eliminate the necessity of cutting tensile
specimens and determining the actual yield strength of the
material under test, one of the following formulas may
be used to determine the maximum allowable working
pressure:
(1) For carbon steel meeting an acceptable Code
specification, with a specified minimum tensile strength of
not over 70,000 psi (480 MPa),
(U.S Customary Units)
P p 0.5H
冢S
S
+ 5000
冣
(SI Units)
P p 0.5H
S
S2
冢S
S
+ 35
冣
(2) For any acceptable material listed in this
Division,
where
P p 0.4H
P0 p maximum allowable working pressure at the
design temperature
Pt p maximum allowable working pressure at test temperature
S p maximum allowable stress value at the design
temperature, as given in the tables referenced in
UG-23 but not to exceed S2
S2 p maximum allowable stress value for the material
used in the test at test temperature as given in the
tables referenced in UG-23
where
H p hydrostatic test pressure at which the test was
stopped, psi (kPa)
Sy p specified minimum yield strength at room temperature, psi (kPa)
Sy avg p actual average yield strength from test specimens at room temperature, psi (kPa)
S p specified minimum tensile strength at room
temperature, psi (kPa)
When the formula in (l)(2)(b)(1) or (l)(2)(b)(2) above
is used, the material in the pressure part shall have had no
appreciable cold working or other treatment that would
tend to raise the yield strength above the normal.
The maximum allowable working pressure at other temperatures shall be determined as provided in (k) above.
UG-101(m) Bursting Test Procedure
UG-101(m)(1) This procedure may be used for vessels or vessel parts under internal pressure when constructed of any material permitted to be used under the
rules of this Division. The maximum allowable working
pressure of any component part proof tested by this method
shall be established by a hydrostatic test to failure by
rupture of a full-size sample of such pressure part. The
UG-101(l) Brittle-Coating Test Procedure
UG-101(l)(1) Subject to the limitations of (a)(2)(a)
above, this procedure may be used only for vessels and
vessel parts under internal pressure, constructed of materials having a definitely determinable yield point (see
SA-370, 13.1). The component parts that require proof
testing shall be coated with a brittle coating in accordance
with (g) above. Pressure shall be applied in accordance with
(h) above. The parts being proof tested shall be examined
between pressure increments for signs of yielding as evidenced by flaking of the brittle coating, or by the appearance of strain lines. The application of pressure shall be
stopped at the first sign of yielding, or if desired, at some
lower pressure.
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2010 SECTION VIII — DIVISION 1
hydrostatic pressure at which rupture occurs shall be determined. Alternatively, the test may be stopped at any pressure before rupture that will satisfy the requirements for
the desired maximum allowable working pressure.
UG-101(m)(2) The maximum allowable working
pressure P in pounds per square inch (kilopascals) at test
temperature for parts tested under this paragraph shall be
computed by one of the following formulas:
(a) parts constructed of materials other than cast
materials:
Pp
applied, readings of the strain gages and the hydrostatic
pressure shall be taken and recorded. The pressure shall
be released and any permanent strain at each gage shall
be determined after any pressure increment that indicates
an increase in strain for this increment over the previous
equal pressure increment. Only one application of each
increment of pressure is required.
UG-101(n)(3) Two curves of strain against test pressure shall be plotted for each gage line as the test progresses, one showing the strain under pressure and one
showing the permanent strain when the pressure is
removed. The test may be discontinued when the test pressure reaches the value H which will, by the formula, justify
the desired working pressure, but shall not exceed the
pressure at which the plotted points for the most highly
strained gage line reaches the value given below for the
material used:
(a) 0.2% permanent strain for aluminum-base and
nickel-base alloys;
(b) 0.2% permanent strain for carbon low alloy
and high alloy steels;
(c) 0.5% strain under pressure for copper-base
alloys.
UG-101(n)(4) The maximum allowable working
pressure P in pounds per square inch (kilopascals) at test
temperature for parts tested under this paragraph shall be
computed by one of the following formulas:
(a) If the average yield strength is determined in
accordance with (j) above,
B
B S E
S E
or P p ⴛ ⴛ 4
S avg
4
S r
(b) parts constructed of cast iron — see UCI-101;
parts constructed of cast ductile iron — see UCD-101;
(c) parts constructed of cast materials, except cast
iron and ductile iron:
Pp
Bf
Bf
S E
S E
or P p
ⴛ ⴛ 4
S avg
4
S r
where
B p bursting test pressure, or hydrostatic test pressure at which the test was stopped
E p efficiency of welded joint, if used (see Table
UW-12)
f p casting quality factor as specified in UG-24
S p specified minimum tensile strength at room
temperature
S avg p average actual tensile strength of test specimens at room temperature
S r p maximum tensile strength of range of specification at room temperature
P p 0.5H
冢S 冣
Sy
y avg
(b) If the actual average yield strength is not determined by test specimens,
The maximum allowable working pressure at other temperatures shall be determined as provided in (k) above.
UG-101(n) Strain Measurement Test Procedure
UG-101(n)(1) Subject to limitations of (a)(2)(a)
above, this procedure may be used for vessels or vessel
parts under internal pressure, constructed of any material
permitted to be used under the rules of this Division. Strains
shall be measured in the direction of the maximum stress
at the most highly stressed parts [see (g) above] by means of
strain gages of any type capable of indicating incremental
strains to 0.00005 in. /in. (0.005%). It is recommended that
the gage length be such that the expected maximum strain
within the gage length does not exceed the expected average strain within the gage length by more than 10%. The
strain gages and the method of attachment shall be shown
by test to be reliable and the results documented for a
range of strain values that is at least 50% higher than
expected, when used with the material surface finish and
configuration being considered. [See (e) above.]
UG-101(n)(2) Pressure shall be applied as provided
in (h) above. After each increment of pressure has been
P p 0.4H
where
H p hydrostatic test pressure at which the test was
stopped in accordance with (n)(3) above
Sy p specified minimum yield strength at room temperature
Sy avg p actual average yield strength from test specimens at room temperature
The maximum allowable working pressure at other temperatures shall be determined as provided in (k) above.
UG-101(o) Displacement Measurement Test Procedure
UG-101(o)(1) Subject to the limitations of (a)(2)(a)
above, this procedure may be used only for vessels and
vessel parts under internal pressure, constructed of materials having a definitely determinable yield point (see
SA-370, 13.1). Displacement shall be measured at the most
highly stressed parts [see (g) above] by means of measuring
devices of any type capable of measuring to 0.001 in.
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2010 SECTION VIII — DIVISION 1
(U.S. Customary Units)
(0.02 mm). The displacement may be measured between
two diametrically opposed reference points in a symmetrical structure, or between a reference point and a fixed base
point. Pressure shall be applied as provided in (h) above.
UG-101(o)(2) After each increment of pressure has
been applied, readings of the displacement and hydrostatic
test pressure shall be taken and recorded. The pressure
shall be released and any permanent displacement shall be
determined after any pressure increment that indicates an
increase in measured displacement for this increment over
the previous equal pressure increment. Only one application of each increment is required. Care must be taken to
assure that the readings represent only displacements of
the parts on which measurements are being made and do
not include any slip of the measuring devices or any movement of the fixed base points or of the pressure part as a
whole.
UG-101(o)(3) Two curves of displacement against
test pressure shall be plotted for each reference point as
the test progresses, one showing the displacement under
pressure and one showing the permanent displacement
when the pressure is removed. The application of pressure
shall be stopped when it is evident that the curve through
the points representing displacement under pressure has
deviated from a straight line.
UG-101(o)(4) The pressure coincident with the proportional limit of the material shall be determined by noting
the pressure at which the curve representing displacement
under pressure deviates from a straight line. The pressure
at the proportional limit may be checked from the curve
of permanent displacement by locating the point where the
permanent displacement begins to increase regularly with
further increases in pressure. Permanent deformation at the
beginning of the curve that results from the equalization
of stresses and irregularities in the material may be disregarded.
UG-101(o)(5) The maximum allowable working
pressure P in pounds per square inch (kilopascals) at test
temperature for parts tested under this paragraph shall be
computed by one of the following formulas.
(a) If the average yield strength is determined in
accordance with (j) above,
P p 0.5H
P p 0.5H
冢S
S
+ 5000
冢S
冣
冣
(SI Units)
P p 0.5H
S
+ 35
(2) For any acceptable material listed in this
Division,
P p 0.4H
where
H p hydrostatic test pressure coincident with the
proportional limit of the weakest element of
the component part tested
Sy p specified minimum yield strength at room temperature
Sy avg p actual average yield strength from test specimens at room temperature
S p specified minimum tensile strength at room
temperature
When the formula in (o)(5)(b)(1) or (o)(5)(b)(2) above is
used, the material in the pressure part shall have had no
appreciable cold working or other treatment that would
tend to raise the yield strength above the normal. The
maximum allowable working pressure at other temperatures shall be determined as provided in (k) above.
UG-101(p) Procedure for Vessels Having Chambers of
Special Shape Subject to Collapse
UG-101(p)(1) Pressure chambers of vessels, portions
of which have a shape other than that of a complete circular
cylinder or formed head, and also jackets of cylindrical
vessels which extend over only a portion of the circumference, which are not fully staybolted as required by
UG-28(i), shall withstand without excessive deformation
a hydrostatic test of not less than three times the desired
maximum allowable working pressure.
UG-101(p)(2) The maximum allowable working
pressure at other temperatures shall be determined as provided in (k) above.
冢S 冣
Sy
UG-102
TEST GAGES
y avg
(a) An indicating gage shall be connected directly to
the vessel. If the indicating gage is not readily visible to
the operator controlling the pressure applied, an additional
indicating gage shall be provided where it will be visible
to the operator throughout the duration of the test. For
large vessels, it is recommended that a recording gage be
used in addition to indicating gages.
(b) Dial indicating pressure gages used in testing shall
be graduated over a range of about double the intended
(b) To eliminate the necessity of cutting tensile
specimens and determining the actual yield strength of the
material under test, one of the following formulas may
be used to determine the maximum allowable working
pressure.
(1) For carbon steel, meeting an acceptable Code
specification, with a specified minimum tensile strength of
not over 70,000 psi (480 MPa),
81
2010 SECTION VIII — DIVISION 1
FIG. UG-116 OFFICIAL SYMBOLS FOR STAMP TO
DENOTE THE AMERICAN SOCIETY OF MECHANICAL
ENGINEERS’ STANDARD
(b) the official UM Symbol shown in Fig. UG-116
sketch (b) on vessels constructed in accordance with the
provisions in U-1(j).
(2) name of the Manufacturer of the pressure vessel
preceded by the words “certified by”;
(3) maximum
allowable
working
pressure37,38
at temperature
;
(4) maximum allowable external working presat temperature
;
sure39
(5) minimum design metal temperature
at
;
maximum allowable working pressure37
(6) Manufacturer’s serial number;
(7) year built.
(b)(1) The type of construction used for the vessel shall
be indicated directly under the Code Symbol by applying
the appropriate letter(s) as follows: vessels having Category A, B, or C joints (except nozzles or other openings
and their attachment) in or joining parts of the vessels:
maximum test pressure, but in no case shall the range be
less than 11⁄2 nor more than 4 times that pressure. Digital
reading pressure gages having a wider range of pressure
may be used provided the readings give the same or greater
degree of accuracy as obtained with dial pressure gages.
(c) All gages shall be calibrated against a standard deadweight tester or a calibrated master gage. Gages shall be
recalibrated at any time that there is reason to believe that
they are in error.
Type of Construction
UG-103
Arc or gas welded
Pressure welded (except resistance)
Brazed
Resistance welded
NONDESTRUCTIVE TESTING
Where magnetic particle examination is prescribed in
this Division it shall be done in accordance with Appendix
6. Where liquid penetrant examination is prescribed it shall
be done in accordance with Appendix 8.
GENERAL
Lethal Service
Unfired Steam Boiler
Direct Firing
(a) The marking and certification of all pressure vessels
built under this Division shall comply with the requirements of the following paragraphs and in addition with
the requirements for Marking and Reports given in the
applicable Parts of Subsections B and C.
(b) The units of measurement used in Manufacturer’s
Data Reports, Manufacturer’s Certificates of Compliance
(UG-120), and capacity certification of pressure relief
devices, and in marking or stamping pressure vessels, pressure vessel parts, and pressure relief devices, required by
this Division, shall be either U.S. Customary units, SI, or
any local customary units. See U-4.
(10)
UG-116
W
P
B
RES
(2) Vessels embodying a combination of types of
construction shall be marked to indicate all of the types
of construction used.
(c) When a vessel is intended for special service and
the special requirements have been complied with [see
UG-120(d)], the appropriate lettering shall be applied as
listed below:
MARKING AND REPORTS
UG-115
Letter(s)
L
UB
DF
This lettering shall be separated by a hyphen and applied
after the lettering of (b) above.
(d) The maximum allowable working pressure and temperature to be indicated on vessels embodying a combination of types of construction and material shall be based on
the most restrictive detail of construction and material used.
(e) When radiographic or ultrasonic examination has
been performed on a vessel in accordance with UW-11,
marking shall be applied under the Code Symbol as
follows:
(1) “RT 1” when all pressure-retaining butt welds,
other than Category B and C butt welds associated with
REQUIRED MARKING
37
When a pressure vessel is expected to operate at more than one
pressure and temperature condition, other values of maximum allowable
working pressure with the coincident permissible temperature may be
added as required. See UG-20(b).
38
The maximum allowable working pressure may be assumed to be
the same as the design pressure when calculations are not made to determine the maximum allowable working pressure.
39
The maximum allowable external working pressure is required only
when specified as a design condition.
(a) Each pressure vessel shall be marked with the following:
(1)(a) the official Code U Symbol shown in Fig.
UG-116 sketch (a) on vessels inspected in accordance with
the requirements in UG-90 through UG-97 (when inspected
by a user’s Inspector as provided in UG-91, the word
USER shall be marked above the Code Symbol); or
82
2010 SECTION VIII — DIVISION 1
nozzles and communicating chambers that neither exceed
NPS 10 (DN 250) nor 11⁄8 in. (29 mm) wall thickness
[except as required by UHT-57(a)], satisfy the full radiography requirements of UW-11(a) for their full length; full
radiography of the above exempted Category B and C butt
welds, if performed, may be recorded on the Manufacturer’s Data Report; or
(2) “RT 2” when the complete vessel satisfies the
requirements of UW-11(a)(5) and when the spot radiography requirements of UW-11(a)(5)(b) have been applied; or
(3) “RT 3” when the complete vessel satisfies the
spot radiography requirements of UW-11(b); or
(4) “RT 4” when only part of the complete vessel
has satisfied the radiographic requirements of UW-11(a)
or where none of the markings “RT 1,” “RT 2,” or “RT
3” are applicable.
The extent of radiography and the applicable joint efficiencies shall be noted on the Manufacturer’s Data Report.
(f)(1) The letters HT shall be applied under the Code
Symbol when the complete vessel has been postweld heat
treated as provided in UW-10.
(2) The letters PHT shall be applied under the Code
Symbol when only part of the complete vessel has been
postweld heat treated as provided in UW-10.
The extent of the postweld heat treatment shall be noted
on the Manufacturer’s Data Report.
(g) The Manufacturer shall have a valid Certificate of
Authorization, and, with the acceptance of the Inspector,
shall apply the Code Symbol to the vessel, which, together
with the final certification [see U-1(j) and UG-120] shall
indicate that all requirements of this Division have been
met.
(1) Except as provided in (2) below, the Code Symbol
shall be applied after the hydrostatic test or pneumatic test.
(2) The Code Symbol may be preapplied to a nameplate. The nameplate may be attached to the vessel after
the final fabrication and examination sequence but before
the hydrostatic tests or pneumatic test provided the procedure for sequence of stamping is described in the Manufacturer’s accepted Quality Control System.
(h)(1) Parts of vessels for which Partial Data Reports
are required in UG-120(c) shall be marked by the parts
Manufacturer, with a nameplate or stamping, with the following:
(a) the official Code Symbol shown in Fig. UG-116
sketch (a), above the word “PART”;
(b) name of the Manufacturer of the part of the
pressure vessel preceded by the words “certified by”;
(c) the Manufacturer’s serial number.
This requirement does not apply to such items as handhole
covers, manhole covers and their accessories. [See (l)
below.]
(h)(2) As an alternative to nameplates or stamping, parts
5 in O.D. and under may be marked with an identification
acceptable to the Inspector and traceable to the Form U2 or Form U-2A Manufacturer’s Partial Data Report. Such
marking shall be of a type that will remain visible until
the parts are installed. The Code Symbol is not required.
(h)(3) No accessory or part of a pressure vessel may be
marked “ASME” or “ASME Std.” unless so specified in
this Division.
(i) All required markings shall be located in a conspicuous place on the vessel, preferably near a manhole or
handhole (see M-3).
(j) Either of the following arrangements may be used in
marking vessels having two or more independent pressure
chambers designed for the same or different operating conditions. Each detachable chamber shall be marked so as
to identify it positively with the combined unit.
(1) The marking may be grouped in one location on
the vessel provided it is arranged so as to indicate clearly
the data applicable to each chamber. This includes the
following, if applicable:
(a) for differential pressure design, the maximum
differential design pressure for each common element [see
UG-19(a)(2) and UHX-19.2.1(a)]
(b) for mean metal temperature design, the maximum mean metal design temperature for each common
element [see UG-19(a)(3) and UHX-19.2.1(b)].
(2) The complete required marking may be applied
to each independent pressure chamber, provided additional
marking, such as stock space, jacket, tubes, or channel
box, is used to indicate clearly to which chamber the data
apply.
(k) In multiple-chamber vessels, only the parts of those
chambers that are required to be built under this Division
(see U-1) need bear the required marking. However, it is
recommended that Manufacturers indicate on such vessels
the working conditions for which the non-Code chambers
were designed.
(l) Removable pressure parts shall be permanently
marked in a manner to identify them with the vessel or
chamber of which they form a part. This does not apply
to manhole covers, handhole covers, and their accessory
parts provided the marking requirements of UG-11 are met.
UG-117
Parts may be stamped with the ASME Code Symbol without being pressure tested prior to shipment. If testing was
not performed, this shall be indicated in the Remarks section of the U-2 and U-2A Manufacturer’s Partial Data
Reports (see Appendix W, Forms U-2 and U-2A).
CERTIFICATES OF
AUTHORIZATION AND CODE
SYMBOL STAMPS
UG-117(a) A Certificate of Authorization to use the
Code U, UM, UV, or UD Symbols shown in Figs. UG-116,
UG-129.1, and UG-129.2 will be granted by the Society
83
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2010 SECTION VIII — DIVISION 1
pursuant to the provisions of the following paragraphs.
Stamps for applying the Code Symbol shall be obtained
from the Society. For those items to be stamped with the
UM, UV, or UD Code Symbol, a Certified Individual shall
provide oversight to ensure that each use of the UM, UV,
or UD Symbol is in accordance with therequirements of
this Division. In addition, each use of the UM, UV, or UD
Code Symbol is to be documented on the Certificate of
Compliance Form (U-3) for UM vessels, or a Certificate
of Conformance Form (UV-1) or (UD-1) as appropriate.
(1) Requirements for the Certified Individual (CI).
The CI shall:
(a) be an employee of the Manufacturer or
Assembler.
(b) be qualified and certified by the Manufacturer
or Assembler. Qualifications shall include as a minimum:
(1) knowledge of the requirements of this Division for the application of the appropriate Code Symbol;
(2) knowledge of the Manufacturer’s or Assembler’s quality program;
(3) training commensurate with the scope, complexity, or special nature of the activities to which oversight
is to be provided.
(c) have a record, maintained and certified by the
Manufacturer or Assembler, containing objective evidence
of the qualifications of the CI and the training program
provided.
(2) Duties of the Certified Individual (CI). The CI
shall:
(a) verify that each item to which the Code Symbol
is applied meets all applicable requirements of this Division
and has a current capacity certification for the “UV” or
“UD” symbols;
(b) for the “UV” or “UD” symbols, review documentation for each lot of items to be stamped to verify,
for the lot, that requirements of this Division have been
completed;
(c) sign the appropriate Certificate of Compliance/
Conformance Form U-3, UV-1, or UD-1 as appropriate
prior to release of control of the item.
(3) Certificate of Compliance/Conformance Forms
U-3, UV-1, or UD-1.
(a) The appropriate Certificate of Conformance
shall be filled out by the Manufacturer or Assembler and
signed by the Certified Individual. Mass produced pressure
relief devices may be recorded on a single entry provided
the devices are identical and produced in the same lot.
(b) The Manufacturer’s or Assembler’s written
quality control program shall include requirements for
completion of Certificates of Conformance forms and
retention by the Manufacturer or Assembler for a minimum
of five years.
UG-117(b) Application for Authorization. Any organization desiring a Certificate of Authorization shall apply
to the Boiler and Pressure Vessel Committee of the Society,
on forms issued by the Society,40 specifying the Stamp
desired and the scope of Code activities to be performed.
When an organization intends to build Code items in plants
in more than one geographical area, either separate applications for each plant or a single application listing the
addresses of all such plants may be submitted. Each application shall identify the Authorized Inspection Agency
providing Code inspection at each plant. A separate Certificate of Authorization will be prepared and a separate
fee charged by the Society for each plant. Applicants for
a UM Certificate of Authorization must already hold an S
or U Certificate.
Each applicant must agree that each Certificate of Authorization and each Code Symbol Stamp are at all times the
property of the Society, that they will be used according
to the rules and regulations of this Division of the Code,
and that they will be promptly returned to the Society
upon demand, or when the applicant discontinues the Code
activities covered by his Certificate, or when the Certificate
of Authorization has expired and no new Certificate has
been issued. The holder of a Code Symbol Stamp shall
not allow any other organization to use it.
UG-117(c) Issuance of Authorization. Authorization to
use Code Symbol Stamps may be granted or withheld by
the Society in its absolute discretion. If authorization is
granted, and the proper administrative fee paid, a Certificate of Authorization evidencing permission to use any
such Symbol, expiring on the triennial anniversary date
thereafter, except for UM Certificates [see (f) below], will
be forwarded to the applicant. Each such certificate will
identify the Code Symbol to be used, and the type of shop
and /or field operations for which authorization is granted
(see Appendix DD). The Certificate will be signed by the
Chairman of the Boiler and Pressure Vessel Committee
and the Director of Accreditation.
Six months prior to the date of expiration of any such
Certificate, the applicant must apply for a renewal of such
authorization and the issuance of a new Certificate. The
Society reserves the absolute right to cancel or refuse to
renew such authorization, returning, pro rata, fees paid
for the unexpired term. The Boiler and Pressure Vessel
Committee may at any time make such regulations concerning the issuance and use of Code Symbol Stamps as it
deems appropriate, and all such regulations shall become
binding upon the holders of any valid Certificates of Authorization.
UG-117(d) Inspection Agreement. As a condition of
obtaining and maintaining a Certificate of Authorization
to use the U or UM Code Symbol Stamps, the Manufacturer
must have in force at all times an inspection contract or
40
The application forms and related information and instructions may
be obtained by writing to the Secretary, ASME Boiler and Pressure Vessel
Committee, Three Park Avenue, New York, NY 10016.
84
2010 SECTION VIII — DIVISION 1
agreement with an Authorized Inspection Agency as
defined in UG-91 to provide inspection services. This
inspection agreement is a written agreement between the
Manufacturer and the Inspection Agency which specifies
the terms and conditions under which the inspection services are to be furnished and which states the mutual
responsibilities of the Manufacturer and the Authorized
Inspectors. A Certificate Holder shall notify the Society
whenever his agreement with an Authorized Inspection
Agency is cancelled or changed to another Authorized
Inspection Agency. Neither Manufacturers nor Assemblers
of pressure relief valves are required to have an inspection
agreement with an Authorized Inspection Agency.
UG-117(e) Quality Control System. Any Manufacturer
or Assembler holding or applying for a Certificate of
Authorization to use the U, UM, UV, or UD Stamp shall
have, and demonstrate, a Quality Control System to establish that all Code requirements, including material, design,
fabrication, examination (by the Manufacturer), inspection
of vessel and vessel parts (by the Authorized Inspector),
pressure testing, and certification will be met. The Quality
Control Systems of UM, UV, or UD Stamp holders shall
include duties of a Certified Individual, as required by this
Division. The Quality Control System shall be in accordance with the requirements of Appendix 10.
UG-117(f) Evaluation for Authorization and Reauthorization. Before issuance or triennial renewal of a Certificate
of Authorization for use of the U or UM Stamp, the Manufacturer’s facilities and organization are subject to a joint
review by a representative of his inspection agency and
an individual certified as an ASME Designee who is
selected by the concerned legal jurisdiction. A written
description or checklist of the Quality Control System
which identifies what documents and what procedures the
Manufacturer will use to produce a Code item shall be
available for review.
A written report to the Society shall be made jointly by
the ASME Designee and the Inspection Agency employed
by the Manufacturer to do his Code inspection. This report
is then reviewed by the Subcommittee on Boiler and Pressure Vessel Accreditation, which will either issue a Certificate of Authorization or notify the applicant of
deficiencies revealed by the review. In such a case, the
applicant will be given an opportunity to explain or correct
these deficiencies.
Certificates of Authorization will be endorsed to indicate
the scope of activity authorized. Authorization may include
field operations if the review team determines that these
operations are adequately described in the quality control
manual, and this determination is accepted by the Society.
Before issuance or renewal of a Certificate of Authorization for use of the UV or UD Stamp, the valve or rupture
disk device Manufacturer’s or Assembler’s facilities and
organization are subject to a review by a representative
from an ASME designated organization. A written description or checklist of the quality control system, which identifies the documents and procedures the Manufacturer or
Assembler will use to produce Code pressure relief valves,
shall be available for review. The representative from an
ASME designated organization shall make a written report
to the Society, where the Subcommittee on Boiler and
Pressure Vessel Accreditation will act on it as described
above.
The purpose of the review is to evaluate the applicant’s
Quality Control System and its implementation. The applicant shall demonstrate sufficient administrative and fabrication functions of the system to show that he has the
knowledge and ability to produce the Code items covered
by his Quality Control System. Fabrication functions may
be demonstrated using current work, a mock-up, or a combination of the two. Additionally, retained records as
required by this Division and the Quality Control System
shall be made available to Authorized Inspector supervisors
or to review teams designated by ASME.
Certificates of Authorization for use of U, UV, and UD
Stamps are valid for 3 years. UM Certificates are valid for
1 year, but reviews after the first and second years of each
3 year period are performed by the Authorized Inspection
Agency only and shall include at a minimum an Authorized
Inspector Supervisor.
The Manufacturer may at any time make changes in
the Quality Control System concerning the methods of
achieving results, subject to acceptance by the Authorized
Inspector. For Manufacturers of mass produced pressure
vessels,41 acceptance of these changes by the ASME Designee is also required. For Manufacturers and Assemblers
of UV stamped pressure relief valves or UD stamped rupture disk devices, such acceptance shall be by the ASME
designated organization.
For those areas where there is no jurisdiction or where
a jurisdiction does not choose to select an ASME Designee
to review a vessel or vessel parts Manufacturer’s facility,
that function shall be performed by an ASME Designee
selected by ASME. Where the jurisdiction is the Manufacturer’s Inspection Agency, the joint review and joint report
shall be made by the jurisdiction and an ASME Designee
selected by ASME.
UG-117(g) Code Construction Before Receipt of Certificate of Authorization. When used to demonstrate his
Quality Control System, a Manufacturer may start fabricating Code items before receipt of a Certificate of Authorization to use a Code Symbol Stamp under the following
conditions.
UG-117(g)(1) The fabrication is done with the participation of the Authorized Inspector and is subject to his
acceptance.
41
See UG-90(c)(2) for additional requirements applicable to mass
produced pressure vessel fabrication.
85
2010 SECTION VIII — DIVISION 1
FIG. UG-118 FORM OF STAMPING
UG-117(g)(2) The activity is in conformance with
the applicant’s Quality Control System.
UG-117(g)(3) The item is stamped with the appropriate Code Symbol and certified once the applicant
receives his Certificate of Authorization from the Society.
Certified by
(Name of Manufacturer)
(Pressure)
at (temperature)
Max. allowable working pressure
UG-118
METHODS OF MARKING
(Pressure)
Nominal Outside Vessel Diameter
Min., in. (mm)
Max., in. (mm)
...
>31⁄2 (89)
>41⁄2 (114)
31⁄2 (89)
41⁄2 (114)
65⁄8 (168)
W (if arc or
(Temperature)
at (pressure)
gas welded)
Min. design metal temperature
RT (if radiographed)
HT (if postweld
heat treated)
Manufacturer’s serial number
Year built
GENERAL NOTE: Information within parentheses is not part of the
required marking. Phrases identifying data may be abbreviated;
minimum abbreviations shall be MAWP, MAEWP, MDMT, S/N, and
year, respectively.
NOTE:
(1) The maximum allowable external working pressure is required only
when specified as a design condition.
Character Size,
Min., in. (mm)
1
⁄8
(3)
⁄16 (5)
1
⁄4 (6)
3
marking arrangement shall be substantially as shown in
Fig. UG-118. Required nameplates shall be located in a
conspicuous place on the vessel [see UG-116(j)].
(b) The nameplate thickness shall be sufficient to resist
distortion due to the application of the marking and to be
compatible with the method of attachment. The nameplate
nominal thickness shall not be less than 0.020 in.
(c) Nameplates may have markings produced by either
casting, etching, embossing, debossing, stamping, or
engraving, except that the Code Symbol shall be stamped
on the nameplate.
(1) The required markings on a nameplate shall be
in characters not less than 5⁄32 in. (4 mm) high, except
that characters for pressure relief device markings may be
smaller.
(2) Characters shall be either indented or raised at
least 0.004 in. (0.10 mm) and shall be legible and readable.
(d) The nameplate may be marked before it is affixed
to the vessel, in which case the Manufacturer shall ensure
that the nameplate with the correct marking has been
applied to the proper vessel, and the Inspector shall satisfy
himself that this has been done.
(e) The nameplate shall be attached to the vessel or to
a pad, bracket, or structure that is welded, brazed, soldered,
or attached with mechanical fasteners directly to the vessel.
Mechanical fasteners shall be of a material and design that
is compatible with the vessel, bracket materials, and the
vessel service. After installation of the pad, bracket, or
structure, the heads of the fasteners shall be welded, brazed,
UG-118(b)(1) For ferrous materials:
(a) the materials shall be limited to P-No. 1 Gr.
Nos. 1 and 2;
(b) the minimum nominal plate thickness shall be
0.1875 in. (5 mm), or the minimum nominal pipe wall
thickness shall be 0.154 in. (4 mm);
(c) the minimum design metal temperature shall
be no colder than −20°F (−29°C);
UG-118(b)(2) For nonferrous materials:
(a) the materials shall be limited to aluminum as
follows: SB-209 Alloys 3003, 5083, 5454, and 6061;
SB-241 Alloys 3003, 5083, 5086, 5454, 6061, and 6063;
and SB-247 Alloys 3003, 5083, and 6061;
(b) the minimum nominal plate thickness shall be
0.249 in. (6.30 mm), or the minimum nominal pipe thickness shall be 0.133 in. (3.38 mm).
UG-118(c) The stamping shall be arranged substantially
as shown in Fig. UG-118 when space permits and shall be
located in a conspicuous place on the vessel [see
UG-116(i)].
UG-119
at (temperature)
Max. allowable external working pressure
[if specified; see Note (1)]
UG-118(a) The required marking shall be stamped
directly on the vessel as provided in (b) and (c) below or
shown on a separate nameplate as provided in UG-119.
UG-118(b) When the marking required by UG-116 is
applied directly to the vessel, it shall be stamped with
letters and figures at least 5⁄16 in. (8 mm) high. Unless the
requirements of (b)(1) or (2) below are met, such stamping
shall not be used on vessels constructed of steel plates less
than 1⁄4 in. (6 mm) thick or of nonferrous plates less than
1
⁄2 in. (13 mm) thick but may be used on vessels constructed
of thicker plates. The character size may be reduced as
shown below for small diameter vessels with space limitations.
NAMEPLATES
(a) Nameplates shall be used on vessels except when
markings are directly applied in accordance with UG-118.
Nameplates shall be metal suitable for the intended service
and shall bear the markings called for in UG-116. The
86
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2010 SECTION VIII — DIVISION 1
or soldered to the pad, bracket, or structure that supports
the nameplate. The nameplate shall be located within 30 in.
(760 mm) of the vessel. Removal shall require the willful
destruction of the nameplate, or its attachment system.
(See M-3.)
(1) Nameplates may be attached either by welding,
brazing, or soldering.
(2) Nameplates may be attached by tamper-resistant
mechanical fasteners of suitable metal construction.
(3) Nameplates may be attached with pressure-sensitive acrylic adhesive systems provided that, in addition to
the requirements of this paragraph, those of Appendix 18
are met.
(f) An additional nameplate in accordance with (a)
through (d) may be installed on the skirt, supports, jacket,
or other permanent attachment to a vessel. All data on the
additional plate, including the Code Symbol, shall be as
required for the mandatory nameplate. The marking need
not be witnessed by the Inspector. The additional nameplate
shall be marked: “DUPLICATE.”
(g) When a nameplate is employed, the Manufacturer’s
name or identifying trademark, and vessel serial number
(or National Board Number, if applicable,) may also be
marked directly on the vessel in close proximity to the
nameplate attachment. The marking shall be of a visible
permanent type that is not detrimental to the vessel, and
its location shall be indicated on the Data Report.
(1) If the thickness limitations of UG-118 preclude
marking directly on the vessel shell or heads, it may be
applied to the skirt, supports, jacket, or other permanent
attachment to the vessel.
(10)
UG-120
exceeding one page, space must be provided for the Manufacturer and Authorized Inspector to initial and date each
of the additional pages. Horizontal spacing for information
on each line may be altered as necessary. All information
must be addressed; however, footnotes described in the
remarks block are acceptable, e.g., for multiple cases of
“none” or “not applicable.”
(3) The Manufacturer shall:
(a) furnish a copy of the Manufacturer’s Data
Report to the user and, upon request, to the Inspector:
(b) submit a copy of the Manufacturer’s Data
Report to the appropriate enforcement authority in the jurisdiction in which the vessel is to be installed, where required
by law;
(c) keep a copy of the Manufacturer’s Data Report
on file in a safe repository for at least 3 years.
In lieu of (c) above, the vessel may be registered and
the Data Report filed with the National Board of Boiler
and Pressure Vessel Inspectors, 1055 Crupper Avenue,
Columbus, Ohio 43229. Where acceptable to the appropriate enforcement authority in the jurisdiction in which
the vessel is to be installed, the vessel may be registered
and the Data Report filed with the National Board of Boiler
and Pressure Vessel Inspectors in lieu of (b) above.
(4) A Manufacturer’s Certificate of Compliance on
Form U-3 shall be completed and signed by the Manufacturer for each pressure vessel marked with the Code UM
Symbol. This Certificate shall be maintained by the Manufacturer for 5 years and a copy made available upon request,
or the vessel may be registered and the Data Report filed
with the National Board of Boiler and Pressure Vessel
Inspectors, 1055 Crupper Avenue, Columbus, OH 43229.
Where acceptable to the appropriate enforcement authority
in the jurisdiction in which the vessel is to be installed,
the vessel may be registered and the Data Report filed
with the National Board of Boiler and Pressure Vessel
Inspectors. Identical vessels up to 1 day’s production may
be recorded on a single Certificate of Compliance.
(b) Both chambers of combination units must be
described on the same Data Report. This includes the following as applicable:
(1) for differential pressure design, the maximum differential design pressure for each common element [see
UG-19(a)(2) and UHX-19.3] and the name of the higher
pressure chamber
(2) for mean metal temperature design, the maximum
mean metal design temperature for each common element
[see UG-19(a)(3) and UHX-19.3]
(c) Partial Data Reports. Data Reports for pressure vessel parts requiring inspection under this Division which
are furnished by other than the location of the Manufacturer
responsible for the vessel to be marked with the Code
Symbol shall be executed on the applicable Partial Data
Report, Form U-2 or Form U-2A, by the parts Manufacturer
DATA REPORTS
(a) A Data Report shall be filled out on Form U-1 or
Form U-1A by the Manufacturer and shall be signed by
the Manufacturer and the Inspector for each pressure vessel
marked with the Code U Symbol.
(1) Same day production of vessels may be reported
on a single Form provided all of the following requirements
are met:
(a) vessels must be identical;
(b) vessels must be manufactured for stock or for
the same user or his designated agent;
(c) serial numbers must be in uninterrupted
sequence; and
(d) the Manufacturer’s written Quality Control
System includes procedures to control the development,
distribution, and retention of the Data Reports.
(2) The number of lines on the Data Report used to
describe multiple components (e.g., nozzles, shell courses)
may be increased or decreased as necessary to provide
space to describe each component. If addition of lines used
to describe multiple components results in the Data Report
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2010 SECTION VIII — DIVISION 1
and his Inspector in accordance with the requirements of
this Division and shall be forwarded, in duplicate, to the
Manufacturer of the completed vessel [see U-2(b)]. Form
U-2A may be used for this purpose provided all the applicable information is recorded on this Form; otherwise Form
U-2 shall be used. These Partial Data Reports, together
with his own inspection, shall be the final Inspector’s
authority to witness the application of a Code Symbol to
the vessel [see UG-90(c)]. When Form U-2 or Form U2A is used, it shall be attached to the associated Form U-1
or Form U-1A by the Manufacturer of the vessel to be
marked with the Code Symbol. Manufacturers with multiple locations, each with its own Certificate of Authorization, may transfer pressure vessel parts from one of its
locations to another without Partial Data Reports, provided
the Quality Control System describes the method of identification, transfer, and receipt of the parts.
(1) Data Reports for those parts of a pressure vessel
which are furnished by a parts Manufacturer to the user
of an existing Code vessel as replacement or repair parts
shall be executed on Form U-2 or U-2A by the parts Manufacturer and his Inspector in accordance with the requirements of this Division. A copy of the parts Manufacturer’s
Partial Data Report shall be furnished to the user or his
designated agent and maintained in accordance with (a)
above.
(2) The parts Manufacturer shall indicate under
“Remarks” the extent he has performed any or all of the
design functions. When the parts Manufacturer performs
only a portion of the design, he shall state which portions
of the design he performed.
(3) Same day production of vessel parts may be
reported on a single Form U-2 or Form U-2A provided all
of the following are met:
(a) vessel parts shall be identical;
(b) Manufacturer’s serial numbers must be in uninterrupted sequence; and
(c) the Manufacturer’s written Quality Control
System includes procedures to control the development,
distribution, and retention of the Partial Data Reports.
(4) For guidance in preparing Partial Data Reports,
see Appendix W.
(d) This Division, in paragraphs such as UW-2, UF-1,
UF-32(b), UB-1, UB-22, UCS-66, UNF-56, UHA-51,
UCL-27, and UHT-6, establishes special requirements to
qualify a vessel for certain “special services.” (Paragraphs,
such as UW-2, prohibit certain types of construction or
materials in some special services.) The special services
to which special requirements are applicable are classified
as follows:
(1) lethal service [for example, see UW-2(a)];
(2) services below certain temperatures (for example,
see UW-2(b), UCS-65, UHA-51, and UHT-6);
(3) unfired steam boiler [for example, see UW-2(c)];
(4) direct firing [for example, see UW-2(d)].
When a vessel is intended for such special services, the
special service and the paragraphs of special requirements
complied with shall be indicated on the Data Reports.
(e) Pressure retaining covers and their attaching bolting
and nuts shall be listed in the Remarks section of the
Manufacturer’s Data Report or on an attached Form U-4
when required. The minimum information shall include
the material specification, material grade, size, and thread
designation.
(f) For sample forms and guidance in their preparation,
see Appendix W.
OVERPRESSURE PROTECTION
UG-125
GENERAL
(a) Other than unfired steam boilers [see UG-125(b)],
all pressure vessels within the scope of this Division, irrespective of size or pressure, shall be provided with overpressure protection in accordance with the requirements
of UG-125 through UG-138 and/or overpressure protection
by system design per UG-140. In addition, the following
shall apply:
(1) It is the user’s or his/her designated agent’s
responsibility to identify all potential overpressure scenarios and the method of overpressure protection used to
mitigate each scenario.
(2) It is the responsibility of the user to ensure that
the required overpressure protection system is properly
installed prior to initial operation.
(3) If a pressure relief device(s) is to be installed, it
is the responsibility of the user or his/her designated agent
to size and select the pressure relief device(s) based on
its intended service. Intended service considerations shall
include, but not necessarily be limited to, the following:
(a) normal operating and upset conditions
(b) fluids
(c) fluid phases
(4) The overpressure protection system need not be
supplied by the vessel Manufacturer.
(5) Unless otherwise defined in this Division, the
definitions relating to pressure relief devices in Section 2
of ASME PTC 25 shall apply.
(b) An unfired steam boiler shall be equipped with pressure relief devices required by Section I insofar as they
are applicable to the service of the particular installation.
(c) Other than unfired steam boilers, when a pressure
relief device is provided, it shall prevent the pressure from
rising more than 10% or 3 psi (20 kPa), whichever is
greater, above the maximum allowable working pressure
except as permitted in (1) and (2) below and UG-127(d)(3).
(See UG-134 for pressure settings.)
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2010 SECTION VIII — DIVISION 1
(e) Pressure relief valves or nonreclosing pressure relief
devices44 may be used to protect against overpressure.
Nonreclosing pressure relief devices may be used either
alone or, if applicable, in combination with pressure relief
valves on vessels.
(1) When multiple pressure relief devices are provided and set in accordance with UG-134(a), they shall
prevent the pressure from rising more than 16% or 4 psi
(30 kPa), whichever is greater, above the maximum allowable working pressure.
(2) When a pressure vessel can be exposed to fire or
other unexpected sources of external heat, the pressure
relief device(s) shall be capable of preventing the pressure
from rising more than 21% above the maximum allowable
working pressure. Supplemental pressure relief devices
shall be installed to protect against this source of excessive
pressure if the pressure relief devices used to satisfy the
capacity requirements of UG-125(c) and UG-125(c)(1)
have insufficient capacity to provide the required protection. See Nonmandatory Appendix M, para. M-13 for cases
where the metal temperature due to fire or other sources
of external heat can cause vessel failure prior to reaching
the MAWP.
(3) Pressure relief devices, intended primarily for
protection against exposure of a pressure vessel to fire or
other unexpected sources of external heat installed on vessels having no permanent supply connection and used for
storage at ambient temperatures of nonrefrigerated liquefied compressed gases,42 are excluded from the requirements of (c)(1) and (c)(2) above, provided:
(a) the pressure relief devices are capable of preventing the pressure from rising more than 20% above the
maximum allowable working pressure of the vessels;
(b) the set pressure marked on these devices shall
not exceed the maximum allowable working pressure of
the vessels;
(c) the vessels have sufficient ullage to avoid a
liquid full condition;
(d) the maximum allowable working pressure of
the vessels on which these pressure relief devices are
installed is greater than the vapor pressure of the stored
liquefied compressed gas at the maximum anticipated temperature43 that the gas will reach under atmospheric conditions; and
(e) pressure relief valves used to satisfy these provisions also comply with the requirements of
UG-129(a)(5), UG-131(c)(2), and UG-134(d)(2).
(d) Pressure relief devices shall be constructed, located,
and installed so that they are readily accessible for testing,
inspection, replacement, and repair and so that they cannot
be readily rendered inoperative (see Appendix M).
NOTE: Use of nonreclosing pressure relief devices of some types may
be advisable on vessels containing substances that may render a pressure
relief valve inoperative, where a loss of valuable material by leakage
should be avoided, or where contamination of the atmosphere by leakage
of noxious fluids must be avoided. The use of rupture disk devices
may also be advisable when very rapid rates of pressure rise may be
encountered.
(f) Vessels that are to operate completely filled with
liquid shall be equipped with pressure relief devices
designed for liquid service, unless otherwise protected
against overpressure.
(g) The pressure relief devices required in (a) above
need not be installed directly on a pressure vessel when
either of the following conditions apply:
(1) the source of pressure is external to the vessel
and is under such positive control that the pressure in
the vessel cannot exceed the maximum allowable working
pressure at the operating temperature except as permitted
in (c) above (see UG-98), or under the conditions set forth
in Appendix M.
(2) there are no intervening stop valves between the
vessel and the pressure relief device or devices except as
permitted under UG-135(d).
NOTE: Pressure reducing valves and similar mechanical or electrical
control instruments, except for pilot operated pressure relief valves as
permitted in UG-126(b), are not considered as sufficiently positive in
action to prevent excess pressures from being developed.
(h) Pressure relief valves for steam service shall meet
the requirements of UG-131(b).
UG-126
PRESSURE RELIEF VALVES45
(a) Safety, safety relief, and relief valves shall be of the
direct spring loaded type.
(b) Pilot operated pressure relief valves may be used,
provided that the pilot is self-actuated and the main valve
44
A pressure relief valve is a pressure relief device which is designed
to reclose and prevent the further flow of fluid after normal conditions
have been restored. A nonreclosing pressure relief device is a pressure
relief device designed to remain open after operation.
45
A safety valve is a pressure relief valve actuated by inlet static
pressure and characterized by rapid opening or pop action. A relief valve
is a pressure relief valve actuated by inlet static pressure which opens
in proportion to the increase in pressure over the opening pressure. A
safety relief valve is a pressure relief valve characterized by rapid opening
or pop action, or by opening in proportion to the increase in pressure
over the opening pressure, depending on application. A pilot operated
pressure relief valve is a pressure relief valve in which the major relieving
device is combined with and is controlled by a self-actuated auxiliary
pressure relief valve.
42
For the purpose of these rules, gases are considered to be substances
having a vapor pressure greater than 40 psia (300 kPa absolute) at
100°F (40°C).
43
Normally this temperature should not be less than 115°F (45°C).
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2010 SECTION VIII — DIVISION 1
will open automatically at not over the set pressure and
will discharge its full rated capacity if some essential part
of the pilot should fail.
(c) The spring in a pressure relief valve shall not be set
for any pressure more than 5% above or below that for
which the valve is marked, unless the setting is within the
spring design range established by the valve Manufacturer
or is determined to be acceptable to the Manufacturer. The
initial adjustment shall be performed by the Manufacturer,
his authorized representative, or an Assembler, and a valve
data tag shall be provided that identifies the set pressure
capacity and date. The valve shall be sealed with a seal
identifying the Manufacturer, his authorized representative,
or the Assembler performing the adjustment.
(d) The set pressure tolerances, plus or minus, of pressure relief valves shall not exceed 2 psi (15 kPa) for pressures up to and including 70 psi (500 kPa) and 3% for
pressures above 70 psi (500 kPa).
UG-127
device shall be determined by a value calculated under the
requirements of (1) or (2) below.
(1) When the rupture disk device discharges
directly to the atmosphere and
(a) is installed within eight pipe diameters
from the vessel nozzle entry; and
(b) with a length of discharge pipe not greater
than five pipe diameters from the rupture disk device; and
(c) the nominal diameters of the inlet and discharge piping are equal to or greater than the stamped NPS
(DN) designator of the device, the calculated relieving
capacity of a pressure relief system shall not exceed a
value based on the applicable theoretical flow equation
[see UG-131(e)(2) and Appendix 11] for the various media
multiplied by a coefficient of discharge K equal to 0.62.
The area A in the theoretical flow equation shall be the
minimum net flow area50 as specified by the rupture disk
device Manufacturer.
(2) The calculated capacity of any pressure relief
system may be determined by analyzing the total system
resistance to flow. This analysis shall take into consideration the flow resistance of the rupture disk device, piping
and piping components including the exit nozzle on the
vessels, elbows, tees, reducers, and valves. The calculation
shall be made using accepted engineering practices for
determining fluid flow through piping systems. This calculated relieving capacity shall be multiplied by a factor of
0.90 or less to allow for uncertainties inherent with this
method. The certified flow resistance51 KR for the rupture
disk device, expressed as the velocity head loss, shall be
determined in accordance with UG-131(k) through (r).
(b) The relieving capacity of the pressure relief
system that uses a rupture disk device as the sole relieving
device shall be determined by taking into consideration
the certified capacity marked on the device and the characteristics of the system fluid and system components
upstream and downstream of the rupture disk device. The
certified coefficient of discharge KD for the rupture disk
device shall be determined in accordance with UG-131(b)
through (j).
(3) Application of Rupture Disks
(a) A rupture disk device may be used as the sole
pressure relieving device on a vessel.
NONRECLOSING PRESSURE RELIEF
DEVICES
(a) Rupture Disk Devices46
(1) General. Every rupture disk shall have a marked
burst pressure established by rules of UG-137(d)(3) within
a manufacturing design range47 at a specified disk temperature48 and shall be marked with a lot49 number. The burst
pressure tolerance at the specified disk temperature shall
not exceed ±2 psi (±15 kPa) for marked burst pressure up
to and including 40 psi (300 kPa) and ±5% for marked
burst pressure above 40 psi (300 kPa).
(2) Relieving Capacity. Rupture disk devices certified
using the flow resistance method shall use (a), and rupture
disk devices certified using the coefficient of discharge
method shall use (b) below.
(a) The rated flow capacity of a pressure relief
system that uses a rupture disk device as the sole relieving
46
A rupture disk device is a nonreclosing pressure relief device actuated
by inlet static pressure and designed to function by the bursting of a
pressure containing disk. A rupture disk is the pressure containing and
pressure sensitive activation component of a rupture disk device. Rupture
disks may be designed in several configurations, such as plain flat, prebulged, or reverse buckling. A rupture disk holder is the structure that
encloses and clamps the rupture disk in position.
47
The manufacturing design range is a range of pressure within which
the marked burst pressure must fall to be acceptable for a particular
requirement as agreed upon between the rupture disk Manufacturer and
the user or his designated agent. The manufacturing design range must
be evaluated in conjuction with the specified burst pressure to ensure
that the marked burst pressure of the rupture disk will always be within
applicable limits of UG-134. Users are cautioned that certain types of
rupture disks have manufacturing ranges that can result in a marked burst
pressure greater than the specified burst pressure.
48
The specified disk temperature supplied to the rupture disk Manufacturer shall be the temperature of the disk when the disk is expected to burst.
49
A lot of rupture disks is those disks manufactured of a material at
the same time, of the same size, thickness, type, heat, and manufacturing
process including heat treatment.
NOTE: When rupture disk devices are used, it is recommended that the
design pressure of the vessel be sufficiently above the intended operating
pressure to provide sufficient margin between operating pressure and
50
The minimum net flow area is the calculated net area after a complete
activation of the rupture disk or pin device with appropriate allowance
for any structural members which may reduce the net flow area through
the device. The net flow area for sizing purposes shall not exceed the
nominal pipe size area of the rupture disk device.
51
The certified flow resistance KR is a dimensionless factor used
to calculate the velocity head loss that results from the presence of a
nonreclosing pressure relief device in a pressure relief system.
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2010 SECTION VIII — DIVISION 1
rupture disk bursting pressure to prevent premature failure of the rupture
disk due to fatigue or creep.
Application of rupture disk devices to liquid service should be carefully
evaluated to assure that the design of the rupture disk device and the
dynamic energy of the system on which it is installed will result in
sufficient opening of the rupture disk.
valve disk and the rupture disk shall be vented or drained
to prevent accumulation of pressure, or suitable means
shall be provided to ensure that an accumulation of pressure
does not affect the proper operation of the pressure relief
valve.55
(2) the pressure relief valve is ample in capacity
to meet the requirements of UG-125(c);
(3) the marked burst pressure of the rupture disk
at the specified disk temperature plus any pressure in the
outlet piping shall not exceed the design pressure of the
outlet portion of the pressure relief valve and any pipe
or fitting between the valve and the rupture disk device.
However, in no case shall the marked burst pressure of
the rupture disk at the specified disk temperature plus any
pressure in the outlet piping exceed the maximum allowable working pressure of the vessel or the set pressure of
the pressure relief valve.
(4) the opening provided through the rupture
disk device after breakage is sufficient to permit a flow
equal to the rated capacity of the attached pressure relief
valve without exceeding the allowable overpressure;
(5) any piping beyond the rupture disk cannot
be obstructed by the rupture disk or fragment;
(6) the system is designed to consider the
adverse effects of any leakage through the pressure relief
valve or through the outlet side rupture disk device, to
ensure system performance and reliability.56
(7) the bonnet of a balancing bellows or diaphragm type pressure relief valve shall be vented to prevent
accumulation of pressure in the bonnet.
(b) Pin Device57
(1) General. Every pin device shall have a marked
set pressure established by the rules of UG-138(d)(4) and
(5) at a specified pin temperature.58 The set pressure tolerance shall not exceed ±2 psi (±15 kPa) for marked set
pressures up to and including 40 psi (300 kPa) and ±5%
for marked set pressures above 40 psi (300 kPa).
(2) Relieving Capacity. Pin devices certified using
the flow resistance method shall use (a) and pin devices
(b) A rupture disk device may be installed between
a pressure relief valve52 and the vessel provided:
(1) the combination of the pressure relief valve
and the rupture disk device is ample in capacity to meet
the requirements of UG-125(c);
(2) the marked capacity of a pressure relief valve
(nozzle type) when installed with a rupture disk device
between the inlet of the valve and the vessel shall be
multiplied by a factor of 0.90 of the rated relieving capacity
of the valve alone, or alternatively, the capacity of such a
combination shall be established in accordance with (3)
below;
(3) the capacity of the combination of the rupture disk device and the pressure relief valve may be established in accordance with the appropriate paragraphs of
UG-132;
(4) the space between a rupture disk device and
a pressure relief valve shall be provided with a pressure
gage, a try cock, free vent, or suitable telltale indicator. This
arrangement permits detection of disk rupture or leakage.53
(5) the opening50provided through the rupture
disk, after burst, is sufficient to permit a flow equal to the
capacity of the valve [(2) and (3) above], and there is no
chance of interference with proper functioning of the valve;
but in no case shall this area be less than the area of the
inlet of the valve unless the capacity and functioning of
the specific combination of rupture disk device and pressure relief valve have been established by test in accordance
with UG-132.
(c) A rupture disk device may be installed on the
outlet side54 of a pressure relief valve which is opened by
direct action of the pressure in the vessel provided:
(1) the pressure relief valve will not fail to open
at its proper pressure setting regardless of any back pressure
that can accumulate between the pressure relief valve disk
and the rupture disk. The space between the pressure relief
55
Users are warned that many types of pressure relief valves will not
open at the set pressure if pressure builds up in the space between the
pressure relief valve disk and the rupture disk device. A specially designed
pressure relief valve such as a diaphragm valve, pilot operated valve, or
a valve equipped with a balancing bellows above the disk may be required.
56
Some adverse effects resulting from leakage may include obstructing
the flow path, corrosion of pressure relief valve components, and undesirable bursts of the outlet side rupture disk.
57
A pin device is a nonreclosing pressure relief device actuated by inlet
static or differential pressure and designed to function by the activation of
a load bearing section of a pin that supports a pressure containing member.
A pin is the load bearing activation component of a pin device its crosssectional area is not limited to a circular shape. A pin device body is the
structure that encloses the pressure containing members.
58
The specified temperature supplied to the pin manufacturer shall be
the temperature of the pin when an emergency condition exists and the
pin is expected to activate.
52
Use of a rupture disk device in combination with a pressure relief
valve shall be carefully evaluated to ensure that the media being handled
and the valve operational characteristics will result in opening of the
valve coincident with the bursting of the rupture disk.
53
Users are warned that a rupture disk will not burst at its design
pressure if back pressure builds up in the space between the disk and
the pressure relief valve which will occur should leakage develop in the
rupture disk due to corrosion or other cause.
54
This use of a rupture disk device in series with the pressure relief
valve is permitted to minimize the loss by leakage through the valve of
valuable or of noxious or otherwise hazardous materials, and where a
rupture disk alone or disk located on the inlet side of the valve is impracticable, or to prevent corrosive gases from a common discharge line from
reaching the valve internals.
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2010 SECTION VIII — DIVISION 1
certified using the coefficient of discharge method shall
use (b) below.
(a) The rated flow capacity of a pressure relief
system that uses a pin device as the sole relieving device
shall be determined by a value calculated under the requirements of (1) or (2) below.
(1) When the pin device discharges directly to
atmosphere and
(a) is installed within eight pipe diameters
from the vessel nozzle entry.
(b) with a length of discharge pipe not greater
than five pipe diameters from the pin device.
(c) the nominal diameters of the inlet and discharge piping are equal to or greater than the stamped NPS
(DN) designator of the device, the calculated relieving
capacity of a pressure relief system shall not exceed a
value based on the applicable theoretical flow equation
[see UG-131(e)(2) and Appendix 11] for the various media
multiplied by a coefficient of discharge K equal to 0.62.
The area A in the theoretical flow equation shall be the
minimum net flow area50 as specified by the pin device
Manufacturer.
(2) The calculated capacity of any pressure relief
system may be determined by analyzing the total system
resistance to flow. This analysis shall take into consideration the flow resistance of the pin device, piping and
piping components including the exit nozzle on the vessels,
elbows, tees, reducers, and valves. The calculation shall be
made using accepted engineering practices for determining
fluid flow through piping systems. This calculated relieving
capacity shall be multiplied by a factor of 0.90 or less
to allow for uncertainties inherent with this method. The
certified flow resistance 51 KR for the pin device, expressed
as the velocity head loss, shall be determined in accordance
with UG-131(k) through (r).
(b) The relieving capacity of the pressure relief
system that uses a pin device as the sole relieving device
shall be determined by taking into consideration the certified capacity marked on the device and the characteristics
of the system fluid and system components upstream and
downstream of the pin device. The certified coefficient of
discharge KD for the pin device shall be determined in
accordance with UG-131(b) through (j).
(3) Application of Pin Devices
(a) A pin device may be used as the sole pressure
relieving device on a vessel.
(b) A pin device may be installed between a pressure relief valve and the vessel provided
(1) the combination of the pressure relief valve
and the pin device is ample in capacity to meet the requirements of UG-125(c)
(2) the combined capacity of the pressure relief
valve and pin device shall be the rated capacity of the valve
multiplied by a factor of 0.90 provided the appropriate
resistance factor KRG, KRGL, or KRL of the device is less
than 6.0 or by a combination capacity factor established
in accordance with the appropriate paragraphs of UG-132.
(3) the space between a pin device and a pressure
relief valve shall be provided with a pressure gage, a try
cock, free vent, or suitable telltale indicator.
(4) the opening 50 provided through the pin
device, after activation, is sufficient to permit flow equal
to the capacity of the valve [(2) above], and there is no
chance of interference with proper functioning of the valve;
but in no case shall this area be less than the area of the
inlet of the valve unless the capacity and functioning of
the specific combination of pin device and pressure relief
valve have been established by test in accordance with
UG-132.
(5) The set pressure of the pin device is equal
to or greater than 90% of the set pressure of the pressure
relief valve.
(c) A pin device shall not be installed on the outlet
side of a pressure relief valve that is opened by direct
action of the pressure in the vessel.
(d) A pin actuated pilot operated pressure relief
device may be used to satisfy the requirements of UG-125,
provided the requirements of UG-125 through UG-136 for
pilot operated pressure relief valves are met.
(c) Spring Loaded Nonreclosing Pressure Relief Device
(1) A spring loaded nonreclosing pressure relief
device, pressure actuated by means which permit the spring
loaded portion of the device to open at the specified set
pressure and remain open until manually reset, may be
used provided the design of the spring loaded nonreclosing
device is such that if the actuating means fail, the device
will achieve full opening at or below its set pressure. Such
a device may not be used in combination with any other
pressure relief device. The tolerance on opening point shall
not exceed ±5%.
(2) The calculated capacity rating of a spring loaded
nonreclosing pressure relief device shall not exceed a value
based on the applicable theoretical formula (see UG-131)
for the various media, multiplied by: K p coefficient p
0.62.
The area A (square inches) in the theoretical formula
shall be the flow area through the minimum opening of
the spring loaded nonreclosing pressure relief device.
(3) In lieu of the method of capacity rating in (2)
above, a Manufacturer may have the capacity of a spring
loaded nonreclosing pressure relief device design certified
in general accordance with the procedures of UG-131, as
applicable.
(d) Open Flow Paths or Vents
(1) Flow paths or vents, open directly or indirectly to
the atmosphere, may be used as the sole pressure relieving
device on a vessel.
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2010 SECTION VIII — DIVISION 1
FIG. UG-129.1 OFFICIAL SYMBOL FOR STAMP TO
DENOTE THE AMERICAN SOCIETY OF MECHANICAL
ENGINEERS’ STANDARD FOR PRESSURE RELIEF
VALVES
(2) The calculated capacity of any pressure relief system may be determined by analyzing the total system resistance to flow. This analysis shall take into consideration
the flow resistance of the piping and piping components
including the exit nozzle on the vessels, elbows, tees,
reducers, and valves. The calculation shall be made using
accepted engineering practices for determining fluid flow
through piping systems. This calculated relieving capacity
shall be multiplied by a factor of 0.90 or less to allow for
uncertainties inherent in this method.
(3) The aggregate capacity of the open flow paths,
or vents, shall be sufficient to prevent overpressure in
excess of those specified in UG-125(c). When the MAWP
is 15 psi (105 kPa) or less, in no case shall the pressure
be allowed to rise more than 21% above the MAWP.
UG-128
(d) In addition to one of the fluids specified above,
the Manufacturer may indicate the capacity in other fluids
(see Appendix 11).
(6) year built, or alternatively, a coding may be
marked on the valve such that the valve Manufacturer or
Assembler can identify the year the valve was assembled
or tested;
(7) ASME Symbol as shown in Fig. UG-129.1. The
pilot of a pilot operated pressure relief valve shall be plainly
marked by the Manufacturer or Assembler showing the
name of the Manufacturer, the Manufacturer’s design or
type number, the set pressure in pounds per square inch
(kPa), and the year built, or alternatively, a coding that the
Manufacturer can use to identify the year built.
LIQUID PRESSURE RELIEF VALVES
Any liquid pressure relief valve used shall be at least
NPS 1⁄2 (DN 15).
(10)
UG-129
MARKING
(a) Safety, Safety Relief, Relief, Liquid Pressure Relief,
and Pilot Operated Pressure Relief Valves. Each safety,
safety relief, relief, liquid pressure relief, and pilot operated
pressure relief valve NPS 1⁄2 (DN 15) and larger shall be
plainly marked by the Manufacturer or Assembler with the
required data in such a way that the marking will not be
obliterated in service. The marking may be placed on the
valve or on a plate or plates that satisfy the requirements
of UG-119:
(1) the name, or an acceptable abbreviation, of the
Manufacturer and the Assembler;
(2) Manufacturer’s design or type number;
(3) NPS size (DN)
(the nominal pipe size
of the valve inlet);
psi (kPa), and, if applicable
(4) set pressure
per UG-136(d)(4), cold differential test pressure
psi (kPa);
(5) certified capacity (as applicable):
(a) lb /hr (kg/hr) of saturated steam at an overpressure of 10% or 3 psi (20 kPa), whichever is greater for
valves certified on steam complying with UG-131(b); or
(b) gal /min (l/min) of water at 70°F (20°C) at an
overpressure of 10% or 3 psi (20 kPa), whichever is greater
for valves certified on water; or
(c) SCFM [standard cubic feet per minute at 60°F
and 14.7 psia] (M3/min, cubic meters per minute at 20°C
and 101 kPa), or lb /min (kg/min), of air at an overpressure
of 10% or 3 psi (kPa), whichever is greater. Valves that
are capacity certified in accordance with UG-131(c)(2)
shall be marked “at 20% overpressure.”
On valves smaller than NPS 1⁄2 (DN 15), the markings may
be made on a metal tag attached by wire or adhesive
meeting the requirements of UG-119 or other means suitable for the service conditions.
(8) Restricted lift
in. (mm) (For restricted
lift valves only)
(b) Safety and safety relief valves certified for a steam
discharging capacity under the provisions of Section I and
bearing the official Code Symbol Stamp of Section I for
safety valves may be used on pressure vessels. The rated
capacity in terms of other fluids shall be determined by
the method of conversion given in Appendix 11. [See
UG-131(h).]
(c) Pressure Relief Valves in Combination With Rupture
Disk Devices. Pressure relief valves in combination with
rupture disk devices shall be marked with the capacity as
established in accordance with UG-127(a)(3)(b)(2) (using
0.90 factor) or the combination capacity factor established
by test in accordance with UG-132(a) or (b), in addition
to the marking of UG-129(a) and (e) below. The marking
may be placed on the pressure relief valve or rupture disk
device or on a plate or plates that satisfy the requirements
of UG-119. The marking shall include the following:
(1) name of Manufacturer of valve;
(2) design or type number of valve;
(3) name of Manufacturer of rupture disk device;
(4) design or type number of rupture disk device;
(5) capacity or combination capacity factor;
93
2010 SECTION VIII — DIVISION 1
FIG. UG-129.2 OFFICIAL SYMBOL FOR STAMP TO
DENOTE THE AMERICAN SOCIETY OF MECHANICAL
ENGINEERS’ STANDARD FOR NONRECLOSING
PRESSURE RELIEF DEVICES
(6) name of organization responsible for this marking. This shall be either the vessel user, vessel Manufacturer, rupture disk Manufacturer, or pressure relief valve
Manufacturer.
(d) Pressure Relief Valves in Combination With Pin
Devices. Pressure relief valves in combination with pin
devices shall be marked with the capacity as established
in accordance with UG-127(b)(3)(b)(2) (using 0.90 factor)
or the combination capacity factor established by test in
accordance with UG-132(a) or (b), in addition to the marking of UG-129(a) and (f) below. The marking may be
placed on the pressure relief valve or pin device or on a
plate or plates that satisfy the requirements of UG-119.
The marking shall include the following:
(1) name of Manufacturer of valve.
(2) design or type number of valve.
(3) name of Manufacturer of pin device.
(4) design or type number of pin device.
(5) capacity or combination capacity factor.
(6) name of organization responsible for this marking. This shall be either the vessel user, vessel Manufacturer, pin device Manufacturer, or pressure relief valve
Manufacturer.
(e) Rupture Disk Devices. Every rupture disk shall be
plainly marked by the Manufacturer in such a way that the
marking will not be obliterated in service. The rupture disk
marking may be placed on the flange of the disk or on a
metal tab that satisfies the requirements of UG-119. The
marking shall include the following:
(1) the name or an acceptable abbreviation of the
Manufacturer;
(2) Manufacturer’s design or type number;
(3) lot number;
(4) disk material;
[NPS (DN) of rupture disk
(5) size
holder];
(6) marked burst pressure
psi (kPa);
(7) specified disk temperature
°F (°C);
(8) minimum net flow area
sq in. (sq
mm);
(9) certified flow resistance (one or more as applicable);
(a) KRG
for rupture disk certified on
air or gases;
for rupture disk certified on
(b) KRL
liquid;
(c) KRGL
for rupture disk certified on
air or gases, and liquid;
(10) ASME symbol as shown in Fig. UG-129.2;
(11) year built, or alternatively, a coding may be
marked on the rupture disk such that the rupture disk device
Manufacturer can identify the year the rupture disk device
was assembled and tested.
Items (1), (2), (5), (10), and (11) above and flow direction
shall also be marked on the rupture disk holder.
(f) Pin Devices and Pin Actuated Pilot Operated Pressure Relief Devices. Pin devices shall be plainly marked
by the Manufacturer with the required data in such a way
that the marking will not be obliterated in service. The
marking may be placed on the device housing or on a plate
or plates that satisfies the requirements of UG-119. The
marking shall include the following:
(1) the name, or an acceptable abbreviation of the
Manufacturer
(2) Manufacturer’s design or type number
(the nominal pipe
(3) NPS (DN) size
size of the device inlet)
(4) set pressure
psi (kPa)
(5) flow direction
(6) pin to pin device identifier
(7) for capacity certified devices
(a) lb/hr of saturated steam at an overpressure 10%
or 3 psi (20 kPa), whichever is greater for devices certified
on steam complying with UG-131(b), or
(b) gal/min of water at 70°F (20°C) at an overpressure of 10% or 3 psi (20 kPa), whichever is greater for
devices certified on water, or
(c) SCFM [standard cubic feet per minute at 60°F
and 14.7 psia (20°C and 101 kPa)], or lb/min, of air at an
overpressure of 10% or 3 psi, whichever is greater. Devices
that are capacity certified in accordance with UG-131(c)(2)
shall be marked “at 20% overpressure.”
(d) In addition to one of the fluids specified above,
the Manufacturer may indicate the capacity in other fluids
(see Appendix 11).
(8) for flow resistance certified devices:
in. 2
(a) minimum net flow area
2
(mm )
(b) certified flow resistance (one or more as applicable)
(1) KRG
for pin devices certified
on air or gases
for pin devices certified
(2) KRL
on liquid
for pin devices certified
(3) KRGL
on air or gases, and liquid
94
2010 SECTION VIII — DIVISION 1
(9) ASME symbol as shown in Fig. UG-129.2
(10) year built, or alternatively, a coding may be
marked on the device such that the device Manufacturer
can identify the year the device was tested
(11) The pin shall be marked according to one of the
following methods:
(a) for pin devices using a replaceable pin to control set pressure, the pin shall be marked with its lot number,
pin temperature58 °F (°C) and the information required by
(f)(1), (f)(4), (f)(6), (f)(10), or
pin devices to be certified for capacity, (b) through (j)
below apply, and for rupture disk and pin devices to be
certified for flow resistance, (k) through (r) below apply
except where noted.
(b)(1) Capacity certification tests for pressure relief
devices for compressible fluids shall be conducted on dry
saturated steam, or air, or gas. When dry saturated steam
is used, the limits for test purposes shall be 98% minimum
quality and 20°F (10°C) maximum superheat. Correction
from within these limits may be made to the dry saturated
condition. Pressure relief devices for steam service may
be rated as above, but at least one device of each series
shall be tested on steam to demonstrate the steam capacity
and performance.
(2) Capacity certification tests for pressure relief
devices for incompressible fluids shall be conducted on
water at a temperature between 40°F (5°C) and 125°F
(50°C).
(c)(1) Capacity certification tests shall be conducted at
a pressure which does not exceed the pressure for which
the pressure relief device is set to operate by more than
10% or 3 psi (20 kPa), whichever is greater, except as
provided in (c)(2) below. For pressure relief valves, minimum pressure for capacity certification tests shall be at
least 3 psi (20 kPa) above set pressure. The reseating
pressure shall be noted and recorded.
(2) Capacity certification tests of pressure relief
devices for use in accordance with UG-125(c)(3) may be
conducted at a pressure not to exceed 120% of the stamped
set pressure of the device.
(3)(a) Pressure relief valves for compressible fluids
having an adjustable blowdown construction shall be
adjusted prior to testing so that the blowdown does not
exceed 5% of the set pressure or 3 psi (20 kPa), whichever
is greater.
(b) The blowdown of pressure relief valves for
incompressible fluids and pressure relief valves for compressible fluids having nonadjustable blowdown shall be
noted and recorded.
(4) Capacity certification of pilot operated pressure
relief devices may be based on tests without the pilot
devices installed, provided prior to capacity tests it has been
demonstrated by test to the satisfaction of the Authorized
Observer that the pilot device will cause the main device
to open fully at a pressure which does not exceed the set
pressure by more than 10% or 3 psi (20 kPa), whichever
is greater, and that the pilot device in combination with
the main device will meet all the requirements of this
Division.
(d)(1) A capacity certification test is required on a set
of three devices for each combination of size, design, and
pressure setting. The stamped capacity rating for each combination of design, size, and test pressure shall not exceed
90% of the average capacity of the three devices tested.
NOTE: When the pin size or configuration does not permit the use of
an attached metal tag, a metal tag may be attached using a nonmetallic
connector with an adhesive that complies with Appendix 18 of this
Division.
(b) for pin devices that are single use and permanently assembled, the marking requirements of (f)(8)(a),
(f)(8)(b), and (f)(11)(a) shall be applied to the device, or
(c) for pin devices that have a replaceable pin
within the sealed body per UG-138, the pin shall be marked
with its lot number.
(g) Spring Loaded Nonreclosing Pressure Relief
Devices. Spring loaded nonreclosing pressure relief devices
shall be marked in accordance with (a) above except that
the Code Symbol Stamp is to be applied only when the
capacity has been established and certified in accordance
with UG-127(c)(3) and all other requirements of UG-130
have been met.
(h) For units other than those included above, see U-4.
UG-130
CODE SYMBOL STAMP
Each pressure relief device59 to which the Code Symbol
Stamp (see Figs. UG-129.1 and UG-129.2) will be applied
shall have been fabricated or assembled by a Manufacturer
or Assembler holding a valid Certificate of Authorization
(UG-117) and capacity certified in accordance with the
requirements of this Division. A Certified Individual (CI)
shall provide oversight as required by UG-117(a). Each
use of the Code Symbol Stamp shall also be documented
on a Certificate of Conformance Form UV-1 or UD-1, as
appropriate.
(10)
UG-131
CERTIFICATION OF CAPACITY OF
PRESSURE RELIEF DEVICES
(a) Before the Code Symbol Stamp is applied to any
pressure relief device, the device Manufacturers shall have
the capacity of their devices certified in accordance with
the provisions of these paragraphs. For pressure relief
valves, (b) through (j) below apply. For rupture disks or
59
Vacuum relief devices are not covered by Code Symbol Stamp
requirements.
95
2010 SECTION VIII — DIVISION 1
The capacity for each set of three devices shall fall within
a range of ±5% of the average capacity. Failure to meet
this requirement shall be cause to refuse certification of
that particular pressure relief device design.
(2) If a Manufacturer wishes to apply the Code Symbol Stamp to a design of pressure relief devices, four
devices of each combination of pipe size and orifice size
shall be tested. These four devices shall be set at pressures
which cover the approximate range of pressures for which
the device will be used or covering the range available at
the certified test facility that shall conduct the tests. The
capacities based on these four tests shall be as follows:
(a) For compressible fluids, the slope W /P of the
actual measured capacity versus the flow pressure for each
test point shall be calculated and averaged:
slope p
(SI Units)
stamped capacity ≤ rated slope (1.20 ⴛ set pressure
+ 100 kPa) or (set pressure + 20 kPa
+ 101 kPa), whichever is greater
For direct spring loaded valves, the results may be
extrapolated to valves with set pressures higher than the
highest set pressure used in the capacity certification tests,
if the spring in the valve with the higher set pressure meets
the requirements of UG-136(a)(2).
(b) For incompressible fluids, the capacities shall
be plotted on log–log paper against the differential (inlet
minus discharge pressure) test pressure and a straight line
drawn through these four points. If the four points do not
establish a straight line, two additional devices shall be
tested for each unsatisfactory point, with a limit of two
unsatisfactory points. Any point that departs from the
straight line by more than 5% should be considered an
unsatisfactory point. The relieving capacity shall be determined from this line. The certified capacity shall not exceed
90% of the capacity taken from the line.
For direct spring loaded valves, the results may be
extrapolated to valves with set pressures higher than the
highest set pressure used in the capacity certification tests,
if the spring in the valve with the higher set pressure meets
the requirements of UG-136(a)(2).
(e) Instead of individual capacity certification as provided in (d) above, a coefficient of discharge K may be
established for a specific pressure relief device design
according to the following procedure.
(1) For each design, the pressure relief device Manufacturer shall submit for test at least three devices for each
of three different sizes (a total of nine devices) together
with detailed drawings showing the device construction.
Each device of a given size shall be set at a different
pressure.
For each valve design intended to be restricted in lift,
the Manufacturer shall have capacity tests conducted on
three valves of different sizes. Each size valve shall be
tested for capacity at the minimum lift for which certification is required, and at two intermediate lift points between
the full rated lift and minimum lift certification points.
Each of the three test valves shall be set at a different
pressure.
For each restricted lift valve tested, it shall be verified
that actual measured capacity at restricted lift will equal
or exceed the ASME rated capacity at full rated lift
multiplied by the ratio of measured restricted lift to full
rated lift.
(2) Tests shall be made on each pressure relief device
to determine its capacity-lift (if applicable), set pressure
and blow-down pressures (for pressure relief valves), and
actual capacity in terms of the fluid used in the test. A
W
measured capacity
p
P
absolute flow pressure, psia
All values derived from the testing must fall within ±5%
of the average value:
minimum slope p 0.95 ⴛ average slope
maximum slope p 1.05 ⴛ average slope
If the values derived from the testing do not fall between
the minimum and maximum slope values, the Authorized
Observer shall require that additional devices be tested at
the rate of two for each device beyond the maximum and
minimum values with a limit of four additional devices.
The relieving capacity to be stamped on the device shall
not exceed 90% of the average slope times the absolute
accumulation pressure:
rated slope p 0.90 ⴛ average slope
(U.S. Customary Units)
stamped capacity ≤ rated slope (1.10 ⴛ set pressure
+ 14.7) or (set pressure + 3 psi
+ 14.7), whichever is greater
(SI Units)
stamped capacity ≤ rated slope (1.10 ⴛ set pressure
+ 100 kPa) or (set pressure + 20 kPa
+ 101 kPa), whichever is greater
For devices certified in accordance with (c)(2) above,
(U.S. Customary Units)
stamped capacity ≤ rated slope (1.20 ⴛ set pressure
+ 14.7) or (set pressure + 3 psi
+ 14.7), whichever is greater
96
2010 SECTION VIII — DIVISION 1
coefficient KD shall be established for each test run as
follows:
KD p
as the coefficient K of that design. The coefficient of the
design shall not be greater than 0.878 (the product of 0.9
ⴛ 0.975).
actual flow
p coefficient of discharge
theoretical flow
NOTE: All experimentally determined coefficients KD shall fall within
a range of ±5% of the average KD found. Failure to meet this requirement
shall be cause to refuse certification of that particular device design.
where actual flow is determined quantitatively by test, and
theoretical flow is calculated by the appropriate formula
which follows:
To convert lb /hr of water to gal /min of water, multiply
the capacity in lb /hr by 1 /500.
(3) The official relieving capacity of all sizes and
pressures of a given design, for which K has been established under the provisions of (e)(2) above, that are manufactured subsequently shall not exceed the value calculated
by the appropriate formula in (e)(2) above multiplied by
the coefficient K (see Appendix 11).
(4) The coefficient shall not be applied to devices
whose beta ratio (ratio of valve throat to inlet diameter)
lies outside the range of 0.15 to 0.75, unless tests have
demonstrated that the individual coefficient of discharge
KD for devices at the extreme ends of a larger range is
within ±5% of the average coefficient K. For designs where
the lift is used to determine the flow area, all devices shall
have the same nominal lift-to-seat diameter ratio (L /D).
(5) The coefficient shall not be applied to direct
spring loaded valves with springs that do not meet the
requirements of UG-136(a)(2).
(6) For direct spring loaded valves the results may
be extrapolated to valves with set pressures higher than
the highest set pressure used in the capacity certification
tests if the spring in the valve with the higher set pressure
meets the requirements of UG-136(a)(2).
(7) For direct spring loaded valves the results may
be extrapolated to valves larger or smaller than the valves
used in the capacity certification tests providing all dimensions of the flow path and all dimensions of the parts that
can affect the overall thrust exercised by the medium on
the moving parts are scaled with the corresponding dimensions of the valves used in the capacity certification testing.
(f) Tests shall be conducted at a place where the testing
facilities, methods, procedures, and person supervising the
tests (Authorized Observer) meet the applicable requirements of ASME PTC 25. The tests shall be made under
the supervision of and certified by an Authorized Observer.
The testing facilities, methods, procedures, and qualifications of the Authorized Observer shall be subject to the
acceptance of the ASME on recommendation of a representative from an ASME designated organization. Acceptance
of the testing facility is subject to review within each 5
year period.
(g) Capacity test data reports for each device model,
type, and size, signed by the Manufacturer and the Authorized Observer witnessing the tests shall be submitted to
For tests with dry saturated steam,
WT p 51.5 AP
NOTE: For dry saturated steam pressures over 1500 psig (10.9 MPa
gage) and up to 3200 psig (22.1 MPa gage), the value of WT, calculated
by the above equation, shall be corrected by being multiplied by the
following factors, which shall be used only if it is 1.0 or greater.
(U.S. Customary Units)
冢 0.2292P − 1061 冣
0.1906P − 1000
(SI Units)
冢 33.2P − 1 061 冣
27.6P − 1 000
For tests with air,
WT p 356AP
冪
M
T
For tests with natural gas,
WT p CAP
冪
M
ZT
For tests with water,
WT p 2407A 冪 (P − Pd ) w
where
A p actual discharge area through the device at developed lift, sq in.
C p constant for gas or vapor based on the ratio of
specific heats
k p cp /cv (see Fig. 11-1)
M p molecular weight
P p (set pressure ⴛ 1.10) plus atmospheric pressure,
psia, or set pressure plus 3 psi (20 kPa) plus
atmospheric pressure, whichever is greater
Pd p pressure at discharge from device
T p absolute temperature at inlet, °F + 460°F (273°C)
w p specific weight of water at device inlet conditions
WT p theoretical flow
Z p compressibility factor corresponding to P and T
The average of the coefficients KD of the nine tests required
shall be multiplied by 0.90, and this product shall be taken
97
2010 SECTION VIII — DIVISION 1
the ASME designated organization for review and acceptance.60 Where changes are made in the design, capacity
certification tests shall be repeated.
(h) For absolute pressures up to 1500 psia (10 MPa
absolute), it is permissible to rate safety valves under
PG-69.1.2 of Section I with capacity ratings at a flow
pressure of 103% of the set pressure, for use on pressure
vessels, without further test. In such instances, the capacity
rating of the valve may be increased to allow for the flow
pressure permitted in (c)(1) and (c)(3) above, namely,
110% of the set pressure, by the multiplier,
pressure relief device for air or gas and liquid service KRGL
may be certified with air or gas as above, but at least one
device of the number required under (o) below for each
size of each series shall be activated with water and flow
tested with air or gas to demonstrate the liquid service flow
resistance.
(m) Flow resistance certification tests shall be conducted
at an inlet pressure which does not exceed 110% of the
device set pressure.
(n)(1) The flow resistance for devices tested with nonpressure containing items, such as seals, support rings, and
vacuum supports, is applicable for the same device design
without seals, support rings, or vacuum supports.
(2) A change in material for rupture disks and their
nonpressure containing disk items, such as seals, support
rings, and vacuum supports, is not considered a design
change and does not require retesting.
(3) Additional linings, coatings, or platings may be
used for the same design of devices provided:
(a) the certificate holder has performed a verification test with the additional linings, coatings, or platings
and has documented that the addition of these materials
does not affect the device opening configuration; and
(b) such verification tests shall be conducted with
devices of the smallest size and minimum set pressure for
which the certified flow resistance with additional materials
is to be used.
(o) Flow resistance certification shall be determined by
one of the following methods:
(1) One Size Method
(a) For each nonreclosing pressure relief device
design, three activation components from the same lot
shall be individually activated and the device tested in
accordance with (p) below. The set pressure shall be the
minimum of the nonreclosing pressure relief device design
of the size tested.
(b) The certified flow resistance KR determined in
(p) below shall apply only to the nonreclosing pressure
relief device design of the size tested.
(c) When additional activation components of the
same design are constructed at a later date, the test results
on the original components may be included as applicable
in the three size method described in (o)(2) below.
(2) Three Size Method
(a) This method of flow resistance certification
may be used for a nonreclosing pressure relief device
design of three or more sizes. The set pressure shall be
the minimum of the activation component for each of the
sizes submitted for test.
(b) For each nonreclosing pressure relief device
design, three activation components from the same lot shall
be activated and the device flow tested in accordance with
(p) below for each of three different sizes of the same
design.
(U.S. Customary Units)
1.10p + 14.7
1.03p + 14.7
(SI Units)
1.10p + 100
1.03p + 100
where
p p set pressure, psig(kPa gage)
Such valves shall be marked in accordance with UG-129.
This multiplier shall not be used as a divisor to transform
test ratings from a higher to a lower flow.
For steam pressures above 1500 psig (10.3 MPa gage),
the above multiplier is not applicable. For pressure relief
valves with relieving pressures between 1500 psig (10.9
MPa gage) and 3200 psig (22.1 MPa gage), the capacity
shall be determined by using the equation for steam and
the correction factor for high pressure steam in (e)(2) above
with the permitted absolute relieving pressure (for Customary units, 1.10p + 14.7; for SI units, 1.10p + 101) and the
coefficient K for that valve design.
(i) Rating of nozzle type pressure relief valves, i.e.,
coefficient KD, greater than 0.90 and nozzle construction,
for saturated water shall be according to 11-2.
(j) When changes are made in the design of a pressure
relief device in such a manner as to affect the flow path,
lift, or performance characteristics of the device, new tests
in accordance with this Division shall be performed.
(k) The certified flow resistance KR of the nonreclosing
pressure relief device used in UG-127(a)(2) or (b)(2) shall
be either KR p 2.4, or as determined in accordance with
(l) through (r) below.
(l) Flow resistance certification tests for nonreclosing
pressure relief device for air or gas service KRG shall be
activated and flow tested with air or gas. Flow resistance
certification tests for liquid service KRL shall be activated
with water and flow tested with air or gas. Nonreclosing
60
Pressure relief device capacities and flow resistances are published in
“Pressure Relief Device Certifications.” This publication may be obtained
from the National Board of Boiler and Pressure Vessel Inspectors, 1055
Crupper Avenue, Columbus, Ohio 43229.
98
2010 SECTION VIII — DIVISION 1
(c) The certified flow resistance KR shall apply to
all sizes and pressures of the design of the nonreclosing
pressure relief device tested.
(p) A certified flow resistance KR may be established
for a specific nonreclosing pressure relief device design
according to the following procedure.
(1) For each design, the nonreclosing pressure relief
device Manufacturer shall submit for test the required
devices in accordance with (o) above together with the
cross section drawings showing the device design.
(2) Tests shall be made on each device to determine
its set pressure and flow resistance at a facility which meets
the requirements of (f) above.
(3) Calculate an average flow resistance using the
individual flow resistances determined in (p)(2) above. All
individual flow resistances shall fall within the average
flow resistance by an acceptance band of plus or minus
three times the average of the absolute values of the deviations of the individual flow resistances from the average
flow resistance. Any individual flow resistance that falls
outside of this band shall be replaced on a two for one
basis. A new average flow resistance shall be computed and
the individual flow resistances evaluated as stated above.
(4) The certified flow resistance KR for a nonreclosing
pressure relief device design shall not be less than zero
and shall not be less than the sum of the average flow
resistance plus three times the average of the absolute
values of the deviations of individual flow resistances from
the average flow resistance.
(q) Flow resistance test data reports for each nonreclosing pressure relief device design, signed by the Manufacturer and the Authorized Observer witnessing the tests,
shall be submitted to the ASME designated organization
for review and acceptance.60
(r) When changes are made in the design of a nonreclosing pressure relief device which affect the flow path or
activation performance characteristics of the device, new
tests in accordance with this Division shall be performed.
UG-132
(2) Capacity certification tests shall be conducted on
saturated steam, air, or natural gas. When saturated steam
is used, corrections for moisture content of the steam shall
be made.
(3) The pressure relief valve Manufacturer or the nonreclosing pressure relief device Manufacturer may submit
for tests the smallest nonreclosing pressure relief device
size with the equivalent size of pressure relief valve that
is intended to be used as a combination device. The pressure
relief valve to be tested shall have the largest orifice used
in the particular inlet size.
(4) Tests may be performed in accordance with the
following subparagraphs. The nonreclosing pressure relief
device and pressure relief valve combination to be tested
shall be arranged to duplicate the combination assembly
design.
(a) The test shall embody the minimum set pressure of the nonreclosing pressure relief device design which
is to be used in combination with the pressure relief valve
design. The marked set pressure of the nonreclosing pressure relief device shall be between 90% and 100% of the
marked set pressure of the valve.
(b) The test procedure to be used shall be as
follows:
The pressure relief valve (one valve) shall be tested for
capacity as an individual valve, without the nonreclosing
pressure relief device at a pressure 10% or 3 psi (20 kPa),
whichever is greater, above the valve set pressure.
The nonreclosing pressure relief device shall then be
installed at the inlet of the pressure relief valve and the
nonreclosing pressure relief device activated to operate
the valve. The capacity test shall be performed on the
combination at 10% or 3 psi (20 kPa), whichever is greater,
above the valve set pressure duplicating the individual
pressure relief valve capacity test.
(c) Tests shall be repeated with two additional activation components of the same nominal rating for a total
of three activation components to be tested with the single
pressure relief valve. The results of the test capacity shall
fall within a range of 10% of the average capacity of the
three tests. Failure to meet this requirement shall be cause
to require retest for determination of cause of the discrepancies.
(d) From the results of the tests, a Combination
Capacity Factor shall be determined. The Combination
Capacity Factor is the ratio of the average capacity determined by the combination tests to the capacity determined
on the individual valve.
The Combination Capacity Factor shall be used as a
multiplier to make appropriate changes in the ASME rated
relieving capacity of the pressure relief valve in all sizes
of the design. The value of the Combination Capacity
Factor shall not be greater than one. The Combination
Capacity Factor shall apply only to combinations of the
CERTIFICATION OF CAPACITY OF
PRESSURE RELIEF VALVES IN
COMBINATION WITH
NONRECLOSING PRESSURE RELIEF
DEVICES
(a) Capacity of Pressure Relief Valves in Combination
With a Nonreclosing Pressure Relief Device at the Inlet
(1) For each combination of pressure relief valve
design and nonreclosing pressure relief device design, the
pressure relief valve Manufacturer or the nonreclosing
pressure relief device Manufacturer may have the capacity
of the combination certified as prescribed in (3) and (4)
below.
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2010 SECTION VIII — DIVISION 1
same design of pressure relief valve and the same design
of nonreclosing pressure relief device as those tested.
(e) The test laboratory shall submit the test results
to the ASME designated organization for acceptance of
the Combination Capacity Factor.61
(b) Optional Testing of Nonreclosing Pressure Relief
Devices and Pressure Relief Valves
(1) If desired, a valve Manufacturer or a nonreclosing
pressure relief device Manufacturer may conduct tests in
the same manner as outlined in (a)(4)(c) and (a)(4)(d) above
using the next two larger sizes of the design of nonreclosing
pressure relief device and pressure relief valve to determine
a Combination Capacity Factor applicable to larger sizes.
If a greater Combination Capacity Factor is established
and can be certified, it may be used for all larger sizes of
the combination, but shall not be greater than one.
(2) If desired, additional tests may be conducted at
higher pressures in accordance with (a)(4)(c) and (a)(4)(d)
above to establish a maximum Combination Capacity Factor to be used at all pressures higher than the highest tested,
but shall not be greater than one.
(d) Heat exchangers and similar vessels shall be protected with a pressure relief device of sufficient capacity
to avoid overpressure in case of an internal failure.
(e) The official rated capacity, or the certified flow
resistance and minimum net flow area, of a pressure relief
device shall be that which is stamped on the device and
guaranteed by the Manufacturer.
(f) The rated pressure relieving capacity of a pressure
relief valve for other than steam or air shall be determined
by the method of conversion given in Appendix 11.
(g) The relieving capacity of a pressure relief device
for compressible fluids may be prorated at any relieving
pressure greater than 1.10p, as permitted under UG-125,
by applying a multiplier to the official relieving capacity
as follows:
(U.S. Customary Units)
P + 14.7
1.10p + 14.7
(SI Units)
P + 101
1.10p + 101
(10)
UG-133
where
DETERMINATION OF PRESSURE
RELIEVING REQUIREMENTS
P p relieving pressure, psig(kPa gage)
p p set pressure, psig(kPa gage)
(a) Except as permitted in (b) below, the aggregate
capacity of the pressure relief devices connected to any
vessel or system of vessels for the release of a liquid, air,
steam, or other vapor shall be sufficient to carry off the
maximum quantity that can be generated or supplied to
the attached equipment without permitting a rise in pressure
within the vessel of more than 16% above the maximum
allowable working pressure when the pressure relief
devices are blowing.
(b) Pressure relief devices as permitted in
UG-125(c)(2), as protection against excessive pressure
caused by exposure to fire or other sources of external
heat, shall have a relieving capacity sufficient to prevent the
pressure from rising more than 21% above the maximum
allowable working pressure of the vessel when all pressure
relief devices are blowing.
(c) Vessels connected together by a system of adequate
piping not containing valves which can isolate any vessel,
and those containing valves in compliance with Appendix
M, M-5, may be considered as one unit in figuring the
required relieving capacity of pressure relief devices to be
furnished.
For steam pressures above 1,500 psig (10 MPa gage),
the above multiplier is not applicable. For steam valves
with relieving pressures greater than 1,500 psig (10 MPa
gage) and less than or equal to 3,200 psig (22.1 MPa gage),
the capacity at relieving pressures greater than 1.10p shall
be determined using the equation for steam and the correction factor for high pressure steam in UG-131(e)(2) with
the permitted absolute relieving pressure and the coefficient
K for that valve design.
(h) When sizing and selecting valves, the restricted lift
nameplate capacity shall be determined by multiplying the
capacity at full rated lift as defined in UG-131(e)(3) by
the ratio of the restricted lift to the full rated lift.
UG-134
PRESSURE SETTINGS AND
PERFORMANCE REQUIREMENTS
(a) When a single pressure relief device is used, the
set pressure61 marked on the device shall not exceed the
maximum allowable working pressure of the vessel. When
the required capacity is provided in more than one pressure
relief device, only one pressure relief device need be set
at or below the maximum allowable working pressure, and
the additional pressure relief devices may be set to open
at higher pressures but in no case at a pressure higher than
105% of the maximum allowable working pressure, except
as provided in (b) below.
61
The set pressure is the value of increasing inlet static pressure at
which a pressure relief device displays one of the operational characteristics as defined by opening pressure, popping pressure, start-to-leak pressure, burst pressure, breaking pressure, or buckling pressure. (The
applicable operating characteristic for a specific device design is specified
by the device Manufacturer.)
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2010 SECTION VIII — DIVISION 1
(b) For pressure relief devices permitted in
UG-125(c)(2) as protection against excessive pressure
caused by exposure to fire or other sources of external
heat, the device marked set pressure shall not exceed 110%
of the maximum allowable working pressure of the vessel.
If such a pressure relief device is used to meet the requirements of both UG-125(c) and UG-125(c)(2), the device
marked set pressure shall not be over the maximum allowable working pressure.
(c) The pressure relief device set pressure shall include
the effects of static head and constant back pressure.
(d)(1) The set pressure tolerance for pressure relief
valves shall not exceed ±2 psi (15 kPa) for pressures up
to and including 70 psi (500 kPa) and ±3% for pressures
above 70 psi (500 kPa), except as covered in (d)(2) below.
(2) The set pressure tolerance of pressure relief valves
which comply with UG-125(c)(3) shall be within −0%,
+10%.
(e) The burst pressure tolerance for rupture disk devices
at the specified disk temperature shall not exceed ±2 psi
(15 kPa) of marked burst pressure up to and including
40 psi (300 kPa) and ±5% of marked burst pressure above
40 psi (300 kPa).
(f) The set pressure tolerance for pin devices shall not
exceed ±2 psi (15 kPa) of marked set pressure up to and
including 40 psi (300 kPa) and ±5% of marked set pressures
above 40 psi (300 kPa) at specified pin temperature.
(g) Pressure relief valves shall be designed and constructed such that when installed per UG-135, the valves
will operate without chattering and shall not flutter at the
flow-rated pressure in a way that either would interfere with
the measurement of capacity or would result in damage.
UG-135
(2) The opening in the vessel wall shall be designed
to provide unobstructed flow between the vessel and its
pressure relief device (see Appendix M).62
(c) When two or more required pressure relief devices
are placed on one connection, the inlet internal cross-sectional area of this connection shall be either sized to avoid
restricting flow to the pressure relief devices or made at
least equal to the combined inlet areas of the safety devices
connected to it. The flow characteristics of the upstream
system shall satisfy the requirements of (b) above. (See
Appendix M.)
(d) There shall be no intervening stop valves between
the vessel and its pressure relief device or devices, or
between the pressure relief device or devices and the point
of discharge, except:
(1) when these stop valves are so constructed or positively controlled that the closing of the maximum number
of block valves possible at one time will not reduce the
pressure relieving capacity provided by the unaffected pressure relief devices below the required relieving capacity; or
(2) under conditions set forth in Appendix M.
(e) The pressure relief devices on all vessels shall be
so installed that their proper functioning will not be hindered by the nature of the vessel’s contents.
(f) Discharge lines from pressure relief devices shall be
designed to facilitate drainage or shall be fitted with drains
to prevent liquid from lodging in the discharge side of the
pressure relief device, and such lines shall lead to a safe
place of discharge. The size of the discharge lines shall be
such that any pressure that may exist or develop will not
reduce the relieving capacity of the pressure relief devices
below that required to properly protect the vessel, or
adversely affect the proper operation of the pressure relief
devices. [See UG-136(a)(8) and Appendix M.]
INSTALLATION
(a) Pressure relief devices intended for relief of compressible fluids shall be connected to the vessel in the vapor
space above any contained liquid or to piping connected
to the vapor space in the vessel which is to be protected.
Pressure relief devices intended for relief of liquids shall
be connected below the liquid level. Alternative connection
locations are permitted, depending on the potential vessel
overpressure scenarios and the type of relief device
selected, provided the requirements of UG-125(a)(2) and
UG-125(c) are met.
(b)(1) The opening through all pipe, fittings, and nonreclosing pressure relief devices (if installed) between a pressure vessel and its pressure relief valve shall have at least
the area of the pressure relief valve inlet. The characteristics
of this upstream system shall be such that the pressure drop
will not reduce the relieving capacity below that required or
adversely affect the proper operation of the pressure relief
valve.
UG-136
MINIMUM REQUIREMENTS FOR
PRESSURE RELIEF VALVES
UG-136(a) Mechanical Requirements
UG-136(a)(1) The design shall incorporate guiding
arrangements necessary to ensure consistent operation and
tightness.
UG-136(a)(2) The spring shall be designed so that
the full lift spring compression shall be no greater than
80% of the nominal solid deflection. The permanent set of
the spring (defined as the difference between the free height
and height measured 10 min after the spring has been
62
Users are warned that the proper operation of nonreclosing pressure
relief devices depends upon following the Manufacturer’s installation
instructions closely with regard to the flow direction marked on the device.
Some device designs will burst at pressures much greater than their
marked burst pressure when installed with the process pressure on the
vent side of the device.
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2010 SECTION VIII — DIVISION 1
as a means of identifying the Manufacturer or Assembler
making the initial adjustment.
UG-136(a)(8) If the design of a pressure relief valve
is such that liquid can collect on the discharge side of the
disk, except as permitted in (a)(9) below, the valve shall
be equipped with a drain at the lowest point where liquid
can collect (for installation, see UG-135).
UG-136(a)(9) Pressure relief valves that cannot be
equipped with a drain as required in (a)(8) above because
of design or application may be used provided:
(a) the pressure relief valves are used only on gas
service where there is neither liquid discharged from the
valve nor liquid formed by condensation on the discharge
side of the valve; and
(b) the pressure relief valves are provided with a
cover or discharge piping per UG-135(f) to prevent liquid
or other contaminant from entering the discharge side of
the valve; and
(c) the pressure relief valve is marked FOR GAS
SERVICE ONLY in addition to the requirements of
UG-129.
UG-136(a)(10) For pressure relief valves of the diaphragm type, the space above the diaphragm shall be vented
to prevent a buildup of pressure above the diaphragm.
Pressure relief valves of the diaphragm type shall be
designed so that failure or deterioration of the diaphragm
material will not impair the ability of the valve to relieve
at the rated capacity.
UG-136(a)(11) Valve capacity, including valves certified per UG-131, may be restricted by restricting the lift
of a valve provided the following requirements are met:
UG-136(a)(11)(a) The valve size shall be NPS 3⁄4
(DN 20) or larger.
UG-136(a)(11)(b) No changes shall be made in the
design of the valve except to change the valve lift by use
of a lift restraining device described in (c) below.
UG-136(a)(11)(c) The restriction of valve capacity
shall be permitted only by the use of a lift restraining
device that shall limit valve lift and shall not otherwise
interfere with flow through the valve. The design of the
lift restraining device shall be subject to review by an
ASME designated organization.
UG-136(a)(11)(d) The lift restraining device shall
be designed so that, if adjustable, the adjustable feature
can be sealed. Seals shall be installed by the valve Manufacturer or Assembler at the time of initial adjustment.
UG-136(a)(11)(e) Valves shall not have their lifts
restricted to a value less than 30% of full rated lift, or less
than 0.080 in. (2 mm).
UG-136(b) Material Selections
UG-136(b)(1) Cast iron seats and disks are not permitted.
UG-136(b)(2) Adjacent sliding surfaces such as
guides and disks or disk holders shall both be of corrosion
compressed solid three additional times after presetting at
room temperature) shall not exceed 0.5% of the free height.
For direct spring loaded valves that have set pressures
above the maximum pressure used in the capacity certification tests, the spring force ratio shall not exceed 1.1 times
the spring force ratio of the valve with the highest set
pressure that was used in the capacity certification tests.
For direct spring loaded valves that have orifices larger
than the largest size used in the capacity certification tests,
the spring force ratio shall not exceed 1.1 times the spring
force ratio of the valve with the largest size orifice in the
capacity certification tests. The spring force ratio, Rsf, shall
be calculated as follows:
Rsf p Fso /Fsc
where
Fsc p force exerted by the spring when the valve is
closed or seated
Fso p force exerted by the spring when the valve is at
rated lift
UG-136(a)(3) Each pressure relief valve on air, water
at the valve inlet that exceeds 140°F (60°C), excluding
overpressure or relief events, or steam service shall have
a substantial lifting device which when activated will
release the seating force on the disk when the pressure
relief valve is subjected to a pressure of at least 75% of
the set pressure of the valve. Pilot operated pressure relief
valves used on these services shall be provided with either
a lifting device as described above or means for connecting
and applying pressure to the pilot adequate to verify that
the moving parts critical to proper operation are free to
move.
UG-136(a)(4) The seat of a pressure relief valve shall
be fastened to the body of the pressure relief valve in such
a way that there is no possibility of the seat lifting.
UG-136(a)(5) In the design of the body of the pressure relief valve, consideration shall be given to minimizing
the effects of deposits.
UG-136(a)(6) Pressure relief valves having threaded
inlet or outlet connections shall be provided with wrenching
surfaces to allow for normal installation without damaging
operating parts.
UG-136(a)(7) Means shall be provided in the design
of all pressure relief valves for use under this Division for
sealing all initial adjustments which can be made without
disassembly of the valve. Seals shall be installed by the
Manufacturer or Assembler at the time of initial adjustment. Seals shall be installed in a manner to prevent changing the adjustment without breaking the seal. For pressure
relief valves larger than NPS 1⁄2 (DN 15), the seal shall serve
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2010 SECTION VIII — DIVISION 1
resistant material. Springs of corrosion resistant material
or having a corrosion resistant coating are required. The
seats and disks of pressure relief valves shall be of suitable
material to resist corrosion by the fluid to be contained.
The Manufacturer shall consider the potential for galling
and the effects on the performance of the pressure relief
valve in the selection of materials for sliding surfaces. The
Manufacturer shall consider the potential for brinelling and
the effects on the performance of the pressure relief valve
in the selection of materials for the seating surfaces.
the following tests are successfully repeated within the
6-month period before expiration.
(a) Two sample production pressure relief valves
of a size and capacity within the capability of an ASME
accepted laboratory shall be selected by a representative
from an ASME designated organization. Pressure relief
valves having adjustable blowdown construction shall have
the control elements positioned by the Manufacturer or
Assembler for a blowdown typical of production methods.
(b) Operational and capacity tests shall be conducted in the presence of a representative from an ASME
designated organization at an ASME accepted laboratory.
The pressure relief valve Manufacturer or Assembler shall
be notified of the time of the test and may have representatives present to witness the test. If a pressure relief valve
with adjustable blowdown construction selected from a
Manufacturer exhibits a blowdown that exceeds 7% of the
set pressure or 3 psi (20 kPa), whichever is greater, during
operational and capacity tests, then an adjustment shall be
made to meet this performance condition, and the operational and capacity tests shall be repeated. This adjustment
may be made on the flow test facility.
(c) Should any pressure relief valve fail to relieve
at or above its certified capacity or should it fail to meet
performance requirements in UG-134, the test shall be
repeated at the rate of two replacement pressure relief
valves, selected in accordance with (c)(3)(a) above, for
each pressure relief valve that failed.
(d) Failure of any of the replacement pressure relief
valves to meet the capacity or the performance requirements of this Division shall be cause for revocation within
60 days of the authorization to use the Code Symbol Stamp
on that particular type of pressure relief valve. During this
period, the Manufacturer or Assembler shall demonstrate
the cause of such deficiency and the action taken to guard
against future occurrence, and the requirements of (c)(3)
above shall apply.
UG-136(c)(4) Use of the Code Symbol Stamp by an
Assembler indicates the use of original, unmodified parts
in strict accordance with the instructions of the Manufacturer of the pressure relief valve.
(a) An assembler may transfer original and unmodified pressure relief parts produced by the Manufacturer to
other Assemblers provided the following conditions are
met:
(1) both Assemblers have been granted permission to apply the V or UV Code Symbol Stamp to the
specific valve type in which the parts are to be used;
(2) the Quality Control System of the Assembler
receiving the pressure relief valve parts shall define the
controls for the procurement and acceptance of those
parts; and
NOTE: The degree of corrosion resistance, appropriate to the intended
service, shall be a matter of agreement between the manufacturer and
the purchaser.
UG-136(b)(3) Materials used in bodies, bonnets or
yokes, and body-to-bonnet or body-to-yoke bolting, shall
be listed in Section II and this Division. Carbon and low
alloy steel bodies, bonnets, yokes and bolting subject to
in-service temperatures colder than −20°F (−30°C) shall
meet the requirements of UCS-66, unless exempted by the
following:
(a) The coincident ratio defined in Fig. UCS-66.1
is 0.35 or less.
(b) The material(s) is exempted from impact testing per Fig. UCS-66.
UG-136(b)(4) Materials used in all other parts
required for the pressure relieving or retaining function
shall be
(a) listed in Section II; or
(b) listed in ASTM specifications; or
(c) controlled by the Manufacturer of the pressure
relief valve by a specification ensuring control of chemical
and physical properties and quality at least equivalent to
ASTM standards.
UG-136(c) Inspection of Manufacturing and /or Assembly of Pressure Relief Valves
UG-136(c)(1) A Manufacturer or Assembler shall
demonstrate to the satisfaction of a representative from
an ASME designated organization that his manufacturing,
production, and testing facilities and quality control procedures will insure close agreement between the performance
of random production samples and the performance of
those valves submitted for Capacity Certification.
UG-136(c)(2) Manufacturing, assembly, inspection,
and test operations including capacity are subject to inspections at any time by a representative from an ASME designated organization.
UG-136(c)(3) A Manufacturer or Assembler may be
granted permission to apply the UV Code Symbol Stamp
to production pressure relief valves capacity certified in
accordance with UG-131 provided the following tests are
successfully completed. This permission shall expire on
the sixth anniversary of the date it is initially granted.
The permission may be extended for 6-year periods if
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2010 SECTION VIII — DIVISION 1
using facilities other than those used by the Manufacturer. An Assembler
may be organizationally independent of a Manufacturer or may be wholly
or partly owned by a Manufacturer.
(3) the pressure relief valve parts are appropriately packaged, marked, or sealed by the Manufacturer to
ensure that the parts are:
(a) produced by the Manufacturer; and
(b) the parts are original and unmodified.
(b) However, an Assembler may convert original
finished parts by either machining to another finished part
or applying a corrosion-resistant coating to valve springs
for a specific application under the following conditions:
(1) Conversions shall be specified by the Manufacturer. Drawings and/or written instructions used for part
conversion shall be obtained from the Manufacturer and
shall include a drawing or description of the converted part
before and after the conversion.
(2) The Assembler’s quality control system, as
accepted by a representative from an ASME designated
organization, must describe in detail the conversion of
original parts, provisions for inspection and acceptance,
personnel training, and control of current Manufacturer’s
drawings and/or written instructions.
(3) The Assembler must document each use of
a converted part and that the part was used in strict accordance with the instructions of the Manufacturer.
(4) The Assembler must demonstrate to the
Manufacturer the ability to perform each type of conversion. The Manufacturer shall document all authorizations
granted to perform part conversions. The Manufacturer
and Assembler shall maintain a file of such authorizations.
(5) For an Assembler to offer restricted lift
valves, the Assembler must demonstrate to the satisfaction
of the Manufacturer the ability to perform valve lift restrictions. The Manufacturer shall document all authorizations
granted to restrict the lift of the valves, and shall maintain
records of lift restrictions made by the Assembler. The
Assembler shall maintain a file of such authorizations.
(6) At least annually a review shall be performed
by the Manufacturer of an Assembler’s system and conversion capabilities. The Manufacturer shall document the
results of these reviews. A copy of this documentation
shall be kept on file by the Assembler. The review results
shall be made available to a representative from an ASME
designated organization.
UG-136(c)(5) In addition to the requirements of
UG-129, the marking shall include the name of the Manufacturer and the final Assembler. The Code Symbol Stamp
shall be that of the final Assembler.
UG-136(d) Production Testing by Manufacturers and
Assemblers
UG-136(d)(1) Each pressure relief valve to which the
Code Symbol Stamp is to be applied shall be subjected to
the following tests by the Manufacturer or Assembler. A
Manufacturer or Assembler shall have a documented program for the application, calibration, and maintenance of
gages and instruments used during these tests.
UG-136(d)(2) Hydrostatic Pressure Test
(a) Hydrostatic testing shall be performed on the
pressure containing parts of the shell of each valve at a
pressure at least 1.5 times the design pressure of the parts.
The valve shell is defined as parts, such as the body, bonnet,
and cap, which isolates primary or secondary pressure from
atmosphere. Parts meeting the following criteria shall be
exempt from hydrostatic testing:
(1) the applied stress under hydrostatic test conditions does not exceed 50% of the allowable stress; and
(2) the part is not cast or welded.
(b) Testing may be performed pneumatically at a
pressure of 1.25 times the design pressure of the part.
Pneumatic testing can be hazardous; it is therefore recommended that special precautions be taken when conducting
a pneumatic test.
(c) Testing may be done in the component or
assembled condition.
(d) These tests shall be conducted after all machining and welding operations on the parts have been completed.
(e) There shall be no visible sign of leakage.
UG-136(d)(3) The secondary pressure zone of each
closed bonnet pressure relief valve exceeding NPS 1
(DN 25) inlet size when such pressure relief valves are
designed for discharge to a closed system shall be tested
with air or other gas at a pressure of at least 30 psi (200 kPa).
There shall be no visible sign of leakage.63
UG-136(d)(4) Each pressure relief valve shall be
tested to demonstrate its popping or set pressure. Pressure
relief valves marked for steam service or having special
internal parts for steam service shall be tested with steam,
except that pressure relief valves beyond the capability of
the production steam test facility either because of size or
set pressure may be tested on air. Necessary corrections
for differentials in popping pressure between steam and
air shall be established by the Manufacturer and applied
to the popping point on air. Pressure relief valves marked
for gas or vapor may be tested with air. Pressure relief
valves marked for liquid service shall be tested with water
NOTE: Within the requirements of UG-136(c) and (d): A Manufacturer
is defined as a person or organization who is completely responsible
for design, material selection, capacity certification, manufacture of all
component parts, assembly, testing, sealing, and shipping of pressure
relief valves certified under this Division. An Assembler is defined as a
person or organization who purchases or receives from a Manufacturer
or another Assembler the necessary component parts or pressure relief
valves and assembles, adjusts, tests, seals, and ships pressure relief valves
certified under this Division, at a geographical location other than and
63
The User may specify a higher test pressure commensurate with the
back pressure anticipated in service.
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2010 SECTION VIII — DIVISION 1
or other suitable liquid. When a valve is adjusted to correct
for service conditions of superimposed back pressure, temperature, or the differential in popping pressure between
steam and air, the actual test pressure (cold differential test
pressure) shall be marked on the valve per UG-129. Test
fixtures and test drums where applicable shall be of adequate size and capacity to ensure that pressure relief valve
action is consistent with the stamped set pressure within
the tolerances required by UG-134(d).
(a) When a direct spring-loaded pressure relief
valve is beyond the production test equipment capabilities,
an alternative test method presented in UG-136(d)(4)(a)(5)
or UG-136(d)(4)(a)(6) may be used, provided all of the
conditions of UG-136(d)(4)(a)(1) through (4) are met:
(1) testing the valve at full pressure may cause
damage to the valve;
(2) the valve lift has been mechanically verified
to meet or exceed the required lift;
(3) for valves with adjustable blowdown, the
blowdown control elements are set to the valve manufacturer’s specification, and
(4) the valve design is compatible with the alternative test method selected.
(5) The valve, with its lift temporarily restricted
during the test, if required to prevent valve damage, shall
be tested on the appropriate media to demonstrate popping
or set pressure.
(6) The valve may be fitted with a hydraulic or
pneumatic lift assist device and tested on the appropriate
media at a pressure less than the valve set pressure. The
lift assist device and test procedure shall be calibrated to
provide the set pressure setting with the tolerance of UG134(d)(1).
UG-136(d)(5) After completion of the tests required
by (d)(4) above, a seat tightness test shall be conducted.
Unless otherwise designated by a Manufacturer’s published
pressure relief valve specification or another specification
agreed to by the user, the seat tightness test and acceptance
criteria shall be in accordance with API 527.
UG-136(d)(6) Testing time on steam pressure relief
valves shall be sufficient, depending on size and design,
to insure that test results are repeatable and representative
of field performance.
UG-136(e) Design Requirements. At the time of the
submission of pressure relief valves for capacity certification, or testing in accordance with (c)(3) above, the ASME
designated organization has the authority to review the
design for conformity with the requirements of UG-136(a)
and UG-136(b) and to reject or require modification of
designs which do not conform, prior to capacity testing.
UG-136(f) Welding and Other Requirements. All welding, brazing, heat treatment, and nondestructive examination used in the construction of bodies, bonnets, and yokes
shall be performed in accordance with the applicable
requirements of this Division.
UG-137
MINIMUM REQUIREMENTS FOR
RUPTURE DISK DEVICES
UG-137(a) Mechanical Requirements
UG-137(a)(1) The design shall incorporate arrangements necessary to ensure consistent operation and
tightness.
UG-137(a)(2) Rupture disk devices having threaded
inlet or outlet connections shall be designed to allow for
normal installation without damaging the rupture disk.
UG-137(b) Material Selections
UG-137(b)(1) The rupture disk material is not
required to conform to a material specification listed in
ASME Section II. The rupture disk material shall be controlled by the Manufacturer of the rupture disk device by
a specification ensuring the control of material properties.
UG-137(b)(2) Materials used in rupture disk holders
and their pressure retaining bolting shall be listed in Section
II and this Division. Carbon and low alloy steel holders
and bolting subject to in-service temperatures colder than
−20°F (−30°C) shall meet the requirements of UCS-66,
unless exempted by the following:
(a) the coincident ratio defined in Fig. UCS-66.1
is 0.40 or less; and
(b) the material(s) is exempted from impact testing
per Fig. UCS-66.
UG-137(b)(3) Materials used in all other parts
required for the pressure relieving or retaining function
shall be
(a) listed in Section II; or
(b) listed in ASTM specifications; or
(c) controlled by the Manufacturer of the rupture
disk device by a specification insuring control of chemical
and physical properties and quality at least equivalent to
ASTM standards.
UG-137(c) Inspection of Manufacturing of Rupture
Disk Devices
UG-137(c)(1) A Manufacturer shall demonstrate to
the satisfaction of a representative of an ASME designated
organization that its manufacturing, production, and testing
facilities and quality control procedures will insure close
agreement between the performance of random production
samples and the performance of those devices submitted
for Certification.
UG-137(c)(2) Manufacturing, assembly, inspection,
and test operations are subject to inspections at any time
by an ASME designee.
UG-137(c)(3) A Manufacturer may be granted permission to apply the UD Code Symbol Stamp to production
rupture disk devices certified in accordance with UG-131
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2010 SECTION VIII — DIVISION 1
provided the following tests are successfully completed.
This permission shall expire on the sixth anniversary of
the date it is initially granted. The permission may be
extended for 6-year periods if the following tests are successfully repeated within the 6-month period before expiration:
(a) Two production sample rupture disk devices
of a size and capacity within the capability of an ASME
accepted laboratory shall be selected by a representative
of an ASME designated organization.
(b) Burst and flow testing shall be conducted in
the presence of a representative of an ASME designated
organization at a place which meets the requirements of
UG-131(f). The device Manufacturer shall be notified of
the time of the test and may have representatives present
to witness the test.
(c) Should any device fail to meet or exceed the
performance requirements (burst pressure, minimum net
flow area, and flow resistance) of UG-127, the test shall
be repeated at the rate of two replacement devices, selected
and tested in accordance with (c)(3)(a) and (c)(3)(b) above
for each device that failed.
(d) Failure of any of the replacement devices to
meet the performance requirements of this Division shall
be cause for revocation within 60 days of the authorization
to use the Code Symbol on that particular type of rupture
disk device design. During this period, the Manufacturer
shall demonstrate the cause of such deficiency and the
action taken to guard against future occurrence, and the
requirements of (c)(3) above shall apply.
UG-137(d) Production Testing by Manufacturers
UG-137(d)(1) Each rupture disk device to which the
Code Symbol Stamp is to be applied shall be subjected to
the following tests by the Manufacturer. The Manufacturer
shall have a documented program for the application, calibration, and maintenance of gages and instruments used
during these tests.
UG-137(d)(2) Hydrostatic Pressure Test
(a) The pressure containing parts of each rupture
disk holder shall be hydrostatically tested at a pressure at
least 1.5 times the design pressure of the parts. Holders
meeting the following criteria shall be exempt from hydrostatic testing:
(1) the applied stress under hydrostatic test conditions does not exceed 50% of the allowable stress; and
(2) the holder is not cast or welded.
(b) Testing may be performed pneumatically at a
pressure of 1.25 times the design pressure of the part.
Pneumatic testing can be hazardous; it is therefore recommended that special precautions be taken when conducting
a pneumatic test.
(c) Testing may be done in the component or
assembled condition.
(d) When the outlet of the device is not designed
to contain pressure, holder components downstream of the
rupture disk are exempt from hydrostatic testing.
(e) Holder components fully contained within the
holder are exempt from hydrostatic testing.
(f) These tests shall be conducted after all machining and welding operations on the parts have been completed.
(g) There shall be no visible sign of leakage.
UG-137(d)(3) Each lot of rupture disks shall be tested
in accordance with one of the following methods. All tests
of disks for a given lot shall be made in a holder of the
same form and pressure area dimensions as that being used
in service. Sample rupture disks, selected from each lot of
rupture disks, shall be made from the same material and
of the same size as those to be used in service. Test results
shall be applicable only to rupture disks used in disk holders
supplied by the rupture disk Manufacturer.
(a) At least two sample rupture disks from each
lot of rupture disks shall be burst at the specified disk
temperature. The marked burst pressure shall be determined so that the sample rupture disk burst pressures are
within the burst pressure tolerance specified by
UG-127(a)(1).
(b) At least four sample rupture disks, but not less
than 5% from each lot of rupture disks, shall be burst at
four different temperatures distributed over the applicable
temperature range for which the disks will be used. This
data shall be used to establish a smooth curve of burst
pressure versus temperature for the lot of disks. The burst
pressure for each data point shall not deviate from the
curve more than the burst pressure tolerance specified in
UG-127(a)(1).
The value for the marked burst pressure shall be derived
from the curve for a specified temperature.
(c) For prebulged solid metal disks or graphite
disks only, at least four sample rupture disks using one
size of disk from each lot of material shall be burst at
four different temperatures, distributed over the applicable
temperature range for which this material will be used.
These data shall be used to establish a smooth curve of
percent change of burst pressure versus temperature for
the lot of material. The acceptance criteria of smooth curve
shall be as in (d)(3)(b) above.
At least two disks from each lot of disks, made from
this lot of material and of the same size as those to be
used, shall be burst at the ambient temperature to establish
the room temperature rating of the lot of disks. The percent
change shall be used to establish the marked burst pressure
at the specified disk temperature for the lot of disks.
UG-137(e) Design Requirements. At the time of the
inspection in accordance with (c)(3) above, a representative
from an ASME designated organization has the authority
to review the design for conformity with the requirements
106
2010 SECTION VIII — DIVISION 1
of UG-137(a) and UG-137(b) and to reject or require modification of designs which to not conform, prior to capacity
testing.
UG-137(f) Welding and Other Requirements. All welding, brazing, heat treatment, and nondestructive examination used in the construction of rupture disk holders and
pressure parts shall be performed in accordance with the
applicable requirements of this Division.
UG-138
(2) Adjacent sliding and sealing surfaces shall both
be of a corrosion-resistant material suitable for use with
the fluid to be contained.
(3) Materials used in bodies and pressure containing
members, excluding proprietary pin material, shall be listed
in Section II and this Division. Carbon and low alloy
steel bodies, pressure containing members, load bearing
members and bolting subject to in service temperatures
colder than −20°F (−30°C) shall meet the requirements of
UCS-66, unless exempted by the following:
(a) The coincident ratio defined in Fig. UCS-66.1
is 0.35 or less.
(b) The material(s) is exempted from impact testing per Fig. UCS-66.
(4) Materials used in all other parts required for the
pressure relieving or retaining function shall be
(a) listed in Section II; or
(b) listed in ASTM specifications; or
(c) controlled by the Manufacturer of the pin
device by a specification ensuring control of chemical and
physical properties and quality at least equivalent to ASTM
specifications.
(5) Materials used for pins shall be controlled by the
Manufacturer of the device by a specification ensuring the
control of material properties.
(c) Inspection of Manufacturing of Pin Devices
(1) A Manufacturer shall demonstrate to the satisfaction of a representative from an ASME designated organization that his manufacturing, production, and testing
facilities and quality control procedures will ensure close
agreement between the performance of random production
samples and the performance of those devices submitted
for Certification.
(2) Manufacturing, assembly, inspection, and test
operations including capacity are subject to inspections at
any time by a representative from an ASME designated
organization.
(3) A Manufacturer may be granted permission to
apply the UD Code Symbol Stamp to production pin
devices certified in accordance with UG-131 provided the
following tests are successfully completed. The permission
shall expire on the fifth anniversary of the date it is initially
granted. The permission may be extended for 5-yr periods
if the following tests are successfully repeated within the
6-mo period before expiration.
(a) Two production sample pin devices of a size
and capacity within the capability of an ASME accepted
laboratory shall be selected by a representative of an ASME
designated organization.
(b) Operational and capacity tests shall be conducted in the presence of a representative from an ASME
designated organization at an ASME accepted laboratory.
The pin device Manufacturer shall be notified of the time
MINIMUM REQUIREMENTS FOR
PIN DEVICES
(a) Mechanical Requirements
(1) The design shall incorporate guiding arrangements necessary to ensure consistent operation and
tightness.
(2) The seat of a pin device shall be fastened to the
body of the pin device in such a way that there is no
possibility of the seat moving from its required position.
(3) In the design of the pin device, consideration shall
be given to minimize the effects of deposits.
(4) Pin devices having threaded inlet or outlet connections shall be provided with wrenching surfaces to allow
for normal installation without damaging operating parts.
(5) Means shall be provided in the design for sealing
all critical parts to ensure that these parts are original and
unmodified. Seals shall be installed in a manner to prevent
changing or modifying parts without breaking the seal. If
the pin is replaceable, this component is not required to be
sealed if it is marked in accordance with UG-129(f)(11)(a).
Seals shall be installed by the Manufacturer. For pin
devices larger than NPS 1⁄2 (DN15), the seal shall serve as
a means of identifying the device Manufacturer.
(6) If the design of the pin device is such that liquid
can collect on the discharge side, except as permitted in
(a)(7) below, the device shall be equipped with a drain at
the lowest point where liquid can collect (for installation,
see UG-135).
(7) Devices that cannot be equipped with a drain as
required in (a)(6) above because of design or application
may be used provided
(a) the devices are used only on gas service where
there is neither liquid discharged from the device nor liquid
formed by condensation on the discharge side of the device
(b) the devices are provided with a cover or discharge piping per UG-135(f) to prevent liquid or other
contaminant from entering the discharge side of the device
(c) the device is marked FOR GAS SERVICE
ONLY in addition to the other required marking
(8) Pins shall be manufactured by the device Manufacturer.
(b) Material Selections
(1) Cast iron seats and disks are not permitted.
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2010 SECTION VIII — DIVISION 1
of the test and may have representatives present to witness
the test.
(c) Should any pin device fail to meet or exceed
performance requirements (set pressure and certified capacity or flow resistance) of UG-127, the test shall be repeated
at the rate of two replacement devices, selected and tested
in accordance with (c)(3)(a) and (c)(3)(b) above for each
device that failed.
(d) Failure of any of the replacement devices to
meet the performance requirements of this Division shall
be cause for revocation within 60 days of the authorization
to use the Code Symbol Stamp on that particular type of
pin device design. During this period, the Manufacturer
shall demonstrate the cause of such deficiency and the
action taken to guard against future occurrence, and the
requirement of (c)(3) above shall apply.
(d) Production Testing by Manufacturers
(1) Each device to which the Code Symbol Stamp is
to be applied shall be subjected to the following tests by the
Manufacturer. The Manufacturer shall have a documented
program for the application, calibration, and maintenance
of gages and instruments used during these tests.
(2) Hydrostatic Pressure Test
(a) The pressure containing parts of each pin
device shall be hydrostatically tested at a pressure at least
1.5 times the design pressure of the parts. Parts meeting
the following criteria shall be exempt from hydrostatic
testing:
(1) the applied stress under hydrostatic test conditions does not exceed 50% of the allowable stress
(2) the part is not cast or welded
(b) Testing may be performed pneumatically at a
pressure of 1.25 times the design pressure of the part.
Pneumatic testing can be hazardous; it is therefore recommended that special precautions be taken when conducting
a pneumatic test.
(c) Testing may be done in the component or
assembled condition.
(d) When the device is designed for discharging
directly to atmosphere, the device components downstream
of the pressure containing element are exempt from hydrostatic testing.
(e) Device components downstream of the pressure
containing element and fully contain within the device are
exempt from hydrostatic testing.
(f) These tests shall be conducted after all machining and welding operations on the parts have been completed.
(g) There shall be no visible sign of leakage.
(3) The secondary pressure zone exceeding NPS 1
(DN 25) inlet size, when such devices are designed for
discharge to a closed system, shall be tested with air or
other gas at a pressure of at least 30 psi (200 kPa). There
shall be no visible signs of leakage.63
(4) Set pressure qualification of a pin device shall be
accomplished by completing set pressure testing in the
device. At least two pins from the same lot shall be tested
in the device. For single use permanently assembled pin
devices having the same specification and configuration,
to be supplied as a single lot, at least two completed devices
shall be tested. The tests shall be conducted at the pin
temperature or according to UG-138(d)(5)(d) below. The
tests shall be within the tolerance defined in UG-127(b)(1).
(5) For all pin lot qualification testing:
(a) Sample pins selected from each lot shall be
made from the same material, heat and of the same critical
dimension as those to be used in service.
(b) Test results shall be applicable only to pins
used in pin devices supplied by the device Manufacturer.
(c) At least two pins or two single-use permanently
assembled pin devices from the same lot shall be tested.
(d) Tests shall be conducted at ambient temperature or the pin temperature (as agreed between device
Manufacturer and user).64 The manufacturer shall establish
a temperature range for which testing at ambient temperature is applicable. For qualification of a pin lot at a single
pin temperature at least two pin tests shall be conducted
at the specified pin temperature.
(e) Pin testing shall be completed in the actual pin
device(s) or using one or more of methods (1) or (2) below.
(1) Lot qualification testing shall be done in a
test pin device of the same form and pressure area dimensions as that in which the pins will be used. At least two
set pressure tests shall be completed at the pin temperature
in accordance with UG-138(d)(5)(d). The tests shall be
within the tolerance defined in UG-127(b)(1).
(2) The set pressure of a lot of pins for a pin
device may be verified by a characterization test that determines the activation loading (force) under device opening
conditions. The following characterization test conditions
shall apply:
(a) The pin retaining arrangement shall be the
same for all characterization tests applied to a pin device.
(b) Using pins from the same lot as tested
under UG-138(d)(4) or UG-138(d)(5)(e)(1), at least two
pins shall be tested to determine the activation force that
correlates to the pin device tested set pressure. The average
of these tests defines the base force that shall be used to
permit further pin qualification using characterization
rather than pin device set pressure testing. The following
shall be used to define a Corrected Base Force that corresponds to the nominal set pressure of the pin device:
Corrected Base Force p
(Nominal Set Pressure) ⴛ (Average Base Force)
Average Tested Set Pressure per UG-138(d)(4) or
UG-138(d)(5)(e)(1)
64
The pin temperature may be different from the operating temperature
for devices where the pin is isolated from operating conditions.
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2010 SECTION VIII — DIVISION 1
(c) The qualification of additional pin quantities or lots may use this Corrected Base Force in place of
pin device set pressure testing provided the pins function
at activation forces that are within ±3% of the Corrected
Base Force for set pressures above 40 psi (275 kPa). For
set pressures below 40 psi (275 kPa), the tested components
shall function at activation forces within a plus/minus tolerance of the Corrected Base Force determined as follows:
management of the operation of the vessel. This documentation shall include as a minimum the following:
(a) detailed process and instrument flow diagrams
(P&IDs), showing all pertinent elements of the system
associated with the vessel
(b) a description of all operating and upset scenarios, including scenarios involving fire and those that result
from operator error, and equipment and/or instrumentation
malfunctions
(c) an analysis showing the maximum coincident
pressure and temperature that can result from each of the
scenarios listed in item UG-140(a)(3)(b) above does not
exceed the MAWP at that temperature
(b) If the pressure is not self-limiting, a pressure vessel
may be protected from overpressure by system design or
by a combination of overpressure by system design and
pressure relief devices, if the following conditions are met.
The rules below are not intended to allow for normal operation above the MAWP at the coincident temperature.
(1) The vessel is not exclusively in air, water, or
steam service unless these services are critical to preventing
the release of fluids that may result in safety or environmental concerns.
(2) The decision to limit the overpressure by system
design is the responsibility of the user. The user shall
request that the Manufacturer’s data report state that overpressure protection is provided by system design per
UG-140(b) if no pressure relief device is to be installed.
If no pressure relief device is to be installed, acceptance
of the jurisdiction may be required.
(3) The user shall conduct a detailed analysis to identify and examine all scenarios that could result in an overpressure condition and magnitude of the overpressure. The
“Causes of Overpressure” as described in ANSI/API Standard 521, Pressure-Relieving and Depressuring Systems,
shall be considered. Other standards or recommended practices that are more appropriate to the specific application
may also be considered. A multidisciplinary team experienced in methods such as hazards and operability analysis
(HazOp); failure modes, effects, and criticality analysis
(FMECA); “what-if” analysis; or other equivalent methodology shall conduct the analysis.
(4) The overpressure scenario shall be readily apparent so that operators or protective instrumentation will take
corrective action to prevent operation above the MAWP
at the coincident temperature.
(5) There shall be no credible overpressure scenario
in which the pressure exceeds 116% of the MAWP times
the ratio of the allowable stress value at the temperature
of the overpressure scenario to the allowable stress value
at the design temperature. The overpressure limit shall
not exceed the test pressure. Credible events or scenario
analysis as described in WRC Bulletin 498 “Guidance
[40 psi (275 kPa)]
ⴛ 3% p
[corresponding nominal set pressure (psi or kPa)]
±% tolerance for actual test forces
(e) Design Requirements. At the time of the inspection
in accordance with UG-138(c)(3) above, a representative
from an ASME designated organization has the authority
to review the design for conformity with the requirements
of UG-138(a) and UG-138(b) and to reject or require modification of designs that do not conform, prior to capacity
testing.
(f) Welding and Other Requirements. All welding, brazing, heat treatment, and nondestructive examination used
in the construction of bodies, bonnets, and yokes shall be
performed in accordance with the applicable requirements
of this Division.
UG-140
OVERPRESSURE PROTECTION BY
SYSTEM DESIGN
(a) A pressure vessel does not require a pressure relief
device if the pressure is self-limiting (e.g., the maximum
discharge pressure of a pump or compressor), and this
pressure is less than or equal to the MAWP of the vessel
at the coincident temperature and the following conditions
are met:
(1) The decision to limit the pressure by system
design is the responsibility of the user. The user shall
request that the Manufacturer’s data report state that overpressure protection is provided by system design per
UG-140(a).
(2) The user shall conduct a detailed analysis to identify and examine all potential overpressure scenarios. The
“Causes of Overpressure” described in ANSI/API Standard
521, Pressure-Relieving and Depressuring Systems, shall
be considered. Other standards or recommended practices
that are more appropriate to the specific application may
also be considered. A multidisciplinary team experienced
in methods such as hazards and operability analysis
(HazOp); failure modes, effects, and criticality analysis
(FMECA); “what-if” analysis; or other equivalent methodology shall establish that there are no sources of pressure
that can exceed the MAWP at the coincident temperature.
(3) The results of the analysis shall be documented
and signed by the individual in responsible charge of the
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2010 SECTION VIII — DIVISION 1
on the Application of Code Case 2211 — Overpressure
Protection by Systems Design” shall be considered.
(6) The results of the analysis shall be documented
and signed by the individual in responsible charge of the
management of the operation of the vessel. This documentation shall include as a minimum the following:
(a) detailed process and instrument flow diagrams
(P&IDs), showing all pertinent elements of the system
associated with the vessel
(b) a description of all operating and upset scenarios, including those involving fire and those that result
from operator error, and equipment and/or instrumentation
malfunctions
(c) a detailed description of any safety critical
instrumentation used to limit the system pressure, including
the identification of all truly independent redundancies and
a reliability evaluation (qualitative or quantitative) of the
overall safety system
(d) an analysis showing the maximum pressure that
can result from each of the scenarios
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2010 SECTION VIII — DIVISION 1
SUBSECTION B
REQUIREMENTS PERTAINING
TO METHODS OF FABRICATION
OF PRESSURE VESSELS
PART UW
REQUIREMENTS FOR PRESSURE VESSELS
FABRICATED BY WELDING
If determined as lethal, the user and /or his designated
agent [see U-2(a)] shall so advise the designer and /or
Manufacturer. It shall be the responsibility of the Manufacturer to comply with the applicable Code provisions (see
UCI-2 and UCD-2).
(1) The joints of various categories (see UW-3) shall
be as follows:
(a) Except under the provisions of (a)(2) or (a)(3)
below, all joints of Category A shall be Type No. (1) of
Table UW-12.
(b) All joints of Categories B and C shall be Type
No. (1) or No. (2) of Table UW-12.
(c) Category C joints for lap joint stub ends shall
be as follows:
(1) The finished stub end shall be attached to its
adjacent shell with a Type No. (1) or Type No. (2) joint
of Table UW-12. The finished stub end can be made from
a forging or can be machined from plate material. [See
UW-13(g).]
(2) The lap joint stub end shall be fabricated as
follows:
(a) The weld is made in two steps as shown
in Fig. UW-13.5.
(b) Before making weld No. 2, weld No. 1 is
examined by full radiography in accordance with UW-51,
regardless of size. The weld and fusion between the weld
GENERAL
UW-1
SCOPE
The rules in Part UW are applicable to pressure vessels
and vessel parts that are fabricated by welding and shall
be used in conjunction with the general requirements in
Subsection A, and with the specific requirements in Subsection C that pertain to the class of material used.
(10)
UW-2
SERVICE RESTRICTIONS
(a) When vessels are to contain lethal1 substances, either
liquid or gaseous, all butt welded joints shall be fully
radiographed, except under the provisions of UW-2(a)(2)
and UW-2(a)(3) below, and UW-11(a)(4). ERW pipe or
tube is not permitted to be used as a shell or nozzle in
lethal service applications. When fabricated of carbon or
low alloy steel, such vessels shall be postweld heat treated.
When a vessel is to contain fluids of such a nature that a
very small amount mixed or unmixed with air is dangerous
to life when inhaled, it shall be the responsibility of the
user and /or his designated agent to determine if it is lethal.
1
By “lethal substances” are meant poisonous gases or liquids of such
a nature that a very small amount of the gas or of the vapor of the liquid
mixed or unmixed with air is dangerous to life when inhaled. For purposes
of this Division, this class includes substances of this nature which are
stored under pressure or may generate a pressure if stored in a closed
vessel.
111
2010 SECTION VIII — DIVISION 1
(4) All joints of Category D shall be full penetration
welds extending through the entire thickness of the vessel
wall or nozzle wall except that partial penetration welds
may be used between materials listed in Table UHA-23
as follows:
(a) for materials shown in UHA-51(d)(1)(a) and
(b) and UHA-51(d)(2)(a) at minimum design metal temperatures (MDMTs) of −320°F (−196°C) and warmer;
(b) for materials shown in UHA-51(d)(1)(c) and
UHA-51(d)(2)(b) at MDMTs of −50°F (−45°C) and
warmer.
(c) Unfired steam boilers with design pressures
exceeding 50 psi (343 kPa) shall satisfy all of the following
requirements:
(1) All joints of Category A (see UW-3) shall be in
accordance with Type No. (1) of Table UW-12, and all
joints in Category B shall be in accordance with Type No.
(1) or No. (2) of Table UW-12.
(2) All butt welded joints shall be fully radiographed
except under the provisions of UW-11(a)(4) and except
for ERW pipe weld seams. When using ERW pipe as the
shell of an unfired steam boiler, its thickness shall not
exceed 1⁄2 in. (13 mm), its diameter shall not exceed 24 in.
(DN 600), and the ERW weld shall be completed using
high frequency (HFI) welding.
(3) When fabricated of carbon or low-alloy steel, such
vessels shall be postweld heat treated.
(4) See also U-1(g), UG-16(b), and UG-125(b).
(d) Pressure vessels or parts subject to direct firing [see
U-1(h)] may be constructed in accordance with all applicable rules of this Division and shall meet the following
requirements:
(1) All welded joints in Category A (see UW-3) shall
be in accordance with Type No. (1) of Table UW-12, and
all welded joints in Category B, when the thickness exceeds
5
⁄8 in. (16 mm), shall be in accordance with Type No. (1)
or No. (2) of Table UW-12. No welded joints of Type No.
(3) of Table UW-12 are permitted for either Category A
or B joints in any thickness.
(2) When the thickness at welded joints exceeds 5⁄8 in.
(16 mm) for carbon (P-No. 1) steels and for all thicknesses
for low alloy steels (other than P-No. 1 steels), postweld
heat treatment is required. For all other material and in
any thickness, the requirements for postweld heat treatment
shall be in conformance with the applicable Subsections
of this Division. See also U-1(g), UG-16(b), and UCS-56.
(3) The user, his designated agent, or the Manufacturer of the vessel shall make available to the Inspector
the calculations used to determine the design temperature
of the vessel. The provisions of UG-20 shall apply except
that pressure parts in vessel areas having joints other than
Type Nos. (1) and (2) of Table UW-12, subject to direct
radiation and /or the products of combustion, shall be
buildup and neck is examined by ultrasonics in accordance
with Appendix 12.
(c) Weld No. 2 is examined by full radiography in accordance with UW-51.
(3) The finished stub end may either conform to
ASME B16.9 dimensional requirements or be made to a
non-standard size, provided all requirements of this Division are met.
(d) All joints of Category D shall be full penetration welds extending through the entire thickness of the
vessel wall or nozzle wall.
(2) Radiographic examination of the welded seam
in exchanger tubes and pipes, to a material specification
permitted by this Division, which are butt welded without
the addition of filler metal may be waived, provided the
tube or pipe is totally enclosed within a shell of a vessel
which meets the requirements of UW-2(a). In the case of
an exchanger, the shell and channel sides must be constructed to the rules for lethal vessels.
(3) If only one side of a heat exchanger contains a
lethal substance, the other side need not be built to the
rules for a vessel in lethal service if:
(a) exchanger tubes are seamless; or
(b) exchanger tubes conform to a tube specification
permitted by this Division, are butt welded without addition
of filler metal, and receive in lieu of full radiography all
of the following nondestructive testing and examination:
(1) hydrotest in accordance with the applicable
specification;
(2) pneumatic test under water in accordance
with the applicable material specification, or if not specified, in accordance with SA-688;
(3) ultrasonic or nondestructive electric examination of sufficient sensitivity to detect surface calibration
notches in any direction in accordance with SA-557, S1
or S3.
No improvement in longitudinal joint efficiency is permitted because of the additional nondestructive tests.
(b) When vessels are to operate below certain temperatures designated by Part UCS (see UCS-68), or impact
tests of the material or weld metal are required by Part
UHA, the joints of various categories (see UW-3) shall be
as follows:
(1) All joints of Category A shall be Type No. (1) of
Table UW-12 except that for austenitic chromium–nickel
stainless steels listed in UHA-51(d)(1)(a) which satisfy
the requirements of UHA-51(f), Type No. (2) joints may
be used.
(2) All joints of Category B shall be Type No. (1) or
No. (2) of Table UW-12.
(3) All joints of Category C shall be full penetration
welds extending through the entire section at the joint.
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2010 SECTION VIII — DIVISION 1
FIG. UW-3 ILLUSTRATION OF WELDED JOINT LOCATIONS TYPICAL OF CATEGORIES A, B, C, AND D
welded joints are butt joints if the half-apex angle, , is
equal to or less than 30 deg and the angle joints when is greater than 30 deg. (See Fig. UW-3.)
(c) Category C. Welded joints connecting flanges, Van
Stone laps, tubesheets, or flat heads to main shell, to formed
heads, to transitions in diameter, to nozzles, or to communicating chambers2 any welded joint connecting one side
plate3 to another side plate of a flat-sided vessel.
(d) Category D. Welded joints connecting communicating chambers2 or nozzles to main shells, to spheres, to
transitions in diameter, to heads, or to flat-sided vessels,
and those joints connecting nozzles to communicating
chambers2 (for nozzles at the small end of a transition in
diameter, see Category B).
designed for temperatures not less than the maximum surface metal temperatures expected under operating conditions.
UW-3
WELDED JOINT CATEGORY
The term “Category” as used herein defines the location
of a joint in a vessel, but not the type of joint. The “Categories” established by this paragraph are for use elsewhere in
this Division in specifying special requirements regarding
joint type and degree of inspection for certain welded pressure joints. Since these special requirements, which are
based on service, material, and thickness, do not apply
to every welded joint, only those joints to which special
requirements apply are included in the categories. The
special requirements will apply to joints of a given category
only when specifically so stated. The joints included in
each category are designated as joints of Categories A,
B, C, and D below. Figure UW-3 illustrates typical joint
locations included in each category.
(a) Category A. Longitudinal and spiral welded joints
within the main shell, communicating chambers,2 transitions in diameter, or nozzles; any welded joint within a
sphere, within a formed or flat head, or within the side
plates3 of a flat-sided vessel; circumferential welded joints
connecting hemispherical heads to main shells, to transitions in diameters, to nozzles, or to communicating
chambers.2
(b) Category B. Circumferential welded joints within
the main shell, communicating chambers,2 nozzles, or transitions in diameter including joints between the transition
and a cylinder at either the large or small end; circumferential welded joints connecting formed heads other than hemispherical to main shells, to transitions in diameter, to
nozzles, or to communicating chambers.2 Circumferential
MATERIALS
UW-5
GENERAL
(a) Pressure Parts. Materials used in the construction
of welded pressure vessels shall comply with the requirements for materials given in UG-4 through UG-15, and
shall be proven of weldable quality. Satisfactory qualification of the welding procedure under Section IX is considered as proof.
(b) Nonpressure Parts. Materials used for nonpressure
parts which are welded to the pressure vessel shall be
proven of weldable quality as described below.
(1) For material identified in accordance with UG-10,
UG-11, UG-15, or UG-93, satisfactory qualification of the
welding procedure under Section IX is considered as proof
of weldable quality.
(2) For materials not identifiable in accordance with
UG-10, UG-11, UG-15, or UG-93, but identifiable as to
nominal chemical analysis and mechanical properties,
S-Number under Section IX, QW/QB-422, or to a material
specification not permitted in this Division, satisfactory
qualification of the welding procedure under Section IX
is considered as proof of weldable quality. For materials
identified by S-Numbers, the provisions of Section IX,
2
Communicating chambers are defined as appurtenances to the vessel
which intersect the shell or heads of a vessel and form an integral part
of the pressure containing enclosure, e.g., sumps.
3
Side plates of a flat-sided vessel are defined as any of the flat plates
forming an integral part of the pressure containing enclosure.
113
2010 SECTION VIII — DIVISION 1
FIG. UW-9 BUTT WELDING OF PLATES OF UNEQUAL THICKNESS
QW/QB-422 may be followed for welding procedure qualification. The welding procedure need only be qualified
once for a given nominal chemical analysis and mechanical
properties or material specification not permitted in this
Division.
(3) Material which cannot be identified may be
proved to be of weldable quality by preparing a butt-joint
test coupon from each piece of nonidentified material to
be used. Guided bend test specimens made from the test
coupon shall pass the tests specified in QW-451 of Section IX.
(c) Two materials of different specifications may be
joined by welding provided the requirements of Section
IX, QW-250, are met.
(d) Materials joined by the electroslag and electrogas
welding processes shall be limited to ferritic steels and the
following austenitic steels which are welded to produce a
ferrite containing weld metal: SA-240 Types 304, 304L,
316, and 316L; SA-182 F304, F304L, F316, and F316L;
SA-351 CF3, CF3A, CF3M, CF8, CF8A, and CF8M.
(e) Materials joined by the inertia and continuous drive
friction welding processes shall be limited to materials
assigned P-Numbers in Section IX and shall not include
rimmed or semikilled steel.
and with the specific requirements for Design in Subsection
C that pertain to the class of material used.
UW-9
(a) Permissible Types. The types of welded joints permitted in arc and gas welding processes are listed in Table
UW-12, together with the limiting plate thickness permitted
for each type. Butt type joints only are permitted with
pressure welding processes [see UW-27(b)].
(b) Welding Grooves. The dimensions and shape of the
edges to be joined shall be such as to permit complete
fusion and complete joint penetration. Qualification of the
welding procedure, as required in UW-28, is acceptable
as proof that the welding groove is satisfactory.
(c) Tapered Transitions. A tapered transition having a
length not less than three times the offset between the
adjacent surfaces of abutting sections, as shown in Fig.
UW-9, shall be provided at joints between sections that
differ in thickness by more than one-fourth of the thickness
of the thinner section, or by more than 1⁄8 in. (3 mm),
whichever is less. The transition may be formed by any
process that will provide a uniform taper. When the transition is formed by removing material from the thicker section, the minimum thickness of that section, after the
material is removed, shall not be less than that required
by UG-23(c). When the transition is formed by adding
additional weld metal beyond what would otherwise be
the edge of the weld, such additional weld metal buildup
shall be subject to the requirements of UW-42. The butt
weld may be partly or entirely in the tapered section or
adjacent to it. This paragraph also applies when there is a
reduction in thickness within a spherical shell or cylindrical
DESIGN
UW-8
DESIGN OF WELDED JOINTS
GENERAL
The rules in the following paragraphs apply specifically
to the design of pressure vessels and vessel parts that are
fabricated by welding and shall be used in conjunction
with the general requirements for Design in Subsection A,
114
2010 SECTION VIII — DIVISION 1
shell course and to a taper at a Category A joint within a
formed head. Provisions for tapers at circumferential, butt
welded joints connecting formed heads to main shells are
contained in UW-13.
(d) Except when the longitudinal joints are radiographed
4 in. (100 mm) each side of each circumferential welded
intersection, vessels made up of two or more courses shall
have the centers of the welded longitudinal joints of adjacent courses staggered or separated by a distance of at
least five times the thickness of the thicker plate.
(e) Lap Joints. For lapped joints, the surface overlap
shall be not less than four times the thickness of the inner
plate except as otherwise provided for heads in UW-13.
(f) Welded Joints Subject to Bending Stresses. Except
where specific details are permitted in other paragraphs,
fillet welds shall be added where necessary to reduce stress
concentration. Corner joints, with fillet welds only, shall
not be used unless the plates forming the corner are properly supported independently of such welds. (See UW-18.)
(g) Minimum Weld Sizes. Sizing of fillet and partial
penetration welds shall take into consideration the loading
conditions in UG-22 but shall not be less than the minimum
sizes specified elsewhere in this Division.
UW-10
(4) all butt welds in nozzles, communicating chambers, etc., attached to vessel sections or heads that are
required to be fully radiographed under (1) or (3) above;
however, except as required by UHT-57(a), Categories B
and C butt welds in nozzles and communicating chambers
that neither exceed NPS 10 (DN 250) nor 11⁄8 in. (29 mm)
wall thickness do not require any radiographic examination;
(5) all Category A and D butt welds in vessel sections
and heads where the design of the joint or part is based
on a joint efficiency permitted by UW-12(a), in which case:
(a) Category A and B welds connecting the vessel
sections or heads shall be of Type No. (1) or Type No.
(2) of Table UW-12;
(b) Category B or C butt welds [but not including
those in nozzles or communicating chambers except as
required in (2) above] which intersect the Category A butt
welds in vessel sections or heads or connect seamless vessel
sections or heads shall, as a minimum, meet the requirements for spot radiography in accordance with UW-52.
Spot radiographs required by this paragraph shall not be
used to satisfy the spot radiography rules as applied to any
other weld increment.
(6) all butt welds joined by electrogas welding with
any single pass greater than 11⁄2 in. (38 mm) and all butt
welds joined by electroslag welding;
(7) ultrasonic examination in accordance with
UW-53 may be substituted for radiography for the final
closure seam of a pressure vessel if the construction of
the vessel does not permit interpretable radiographs in
accordance with Code requirements. The absence of suitable radiographic equipment shall not be justification for
such substitution.
(8) exemptions from radiographic examination for
certain welds in nozzles and communicating chambers as
described in (2), (4), and (5) above take precedence over the
radiographic requirements of Subsection C of this Division.
(b) Spot Radiography. Except when spot radiography
is required for Category B or C butt welds by (a)(5)(b)
above, butt welded joints made in accordance with Type
No. (1) or (2) of Table UW-12 which are not required to
be fully radiographed by (a) above, may be examined by
spot radiography. Spot radiography shall be in accordance
with UW-52. If spot radiography is specified for the entire
vessel, radiographic examination is not required of Category B and C butt welds in nozzles and communicating
chambers that exceed neither NPS 10 (DN 250) nor 11⁄8
in. (29 mm) wall thickness.
POSTWELD HEAT TREATMENT
Pressure vessels and pressure vessel parts shall be postweld heat treated as prescribed in UW-40 when postweld
heat treatment is required in the applicable part of Subsection C.
UW-11
RADIOGRAPHIC AND ULTRASONIC
EXAMINATION
(a) Full Radiography. The following welded joints shall
be examined radiographically for their full length in the
manner prescribed in UW-51:
(1) all butt welds in the shell and heads of vessels
used to contain lethal substances [see UW-2(a)];
(2) all butt welds in vessels in which the nominal
thickness [see (g) below] at the welded joint exceeds 11⁄2
in. (38 mm), or exceeds the lesser thicknesses prescribed
in UCS-57, UNF-57, UHA-33, UCL-35, or UCL-36 for
the materials covered therein, or as otherwise prescribed
in UHT-57, ULW-51, ULW-52(d), ULW-54, or ULT-57;
however, except as required by UHT-57(a), Categories B
and C butt welds in nozzles and communicating chambers
that neither exceed NPS 10 (DN 250) nor 11⁄8 in. (29 mm)
wall thickness do not require any radiographic examination;
(3) all butt welds in the shell and heads of unfired
steam boilers having design pressures exceeding 50 psi
(350 kPa) [see UW-2(c)];
NOTE: This requirement specifies spot radiography for butt welds of
Type No. (1) or No. (2) that are used in a vessel, but does not preclude
the use of fillet and /or corner welds permitted by other paragraphs, such
as for nozzle and manhole attachments, welded stays, flat heads, etc.,
which need not be spot radiographed.
115
2010 SECTION VIII — DIVISION 1
(c) No Radiography. Except as required in (a) above,
no radiographic examination of welded joints is required
when the vessel or vessel part is designed for external
pressure only, or when the joint design complies with
UW-12(c).
(d) Electrogas welds in ferritic materials with any single
pass greater that 11⁄2 in. (38 mm) and electroslag welds in
ferritic materials shall be ultrasonically examined throughout their entire length in accordance with the requirements
of Appendix 12. This ultrasonic examination shall be done
following the grain refining (austenitizing) heat treatment
or postweld heat treatment.
(e) In addition to the requirements in (a) and (b) above,
all welds made by the electron beam process shall be
ultrasonically examined for their entire length in accordance with the requirements of Appendix 12.
(f) When radiography is required for a welded joint in
accordance with (a) and (b) above, and the weld is made
by the inertia and continuous drive friction welding processes, the welded joints shall also be ultrasonically examined for their entire length in accordance with Appendix 12.
(g) For radiographic and ultrasonic examination of butt
welds, the definition of nominal thickness at the welded
joint under consideration shall be the nominal thickness
of the thinner of the two parts joined. Nominal thickness
is defined in 3-2.
UW-12
for welded joints that are neither fully radiographed nor
spot radiographed [see UW-11(c)].
(d) Seamless vessel sections or heads shall be considered equivalent to welded parts of the same geometry in
which all Category A welds are Type No. 1. For calculations involving circumferential stress in seamless vessel
sections or for thickness of seamless heads, E p 1.0 when
the spot radiography requirements of UW-11(a)(5)(b) are
met. E p 0.85 when the spot radiography requirements
of UW-11(a)(5)(b) are not met, or when the Category A
or B welds connecting seamless vessel sections or heads
are Type No. 3, 4, 5, or 6 of Table UW-12.
(e) Welded pipe or tubing shall be treated in the same
manner as seamless, but with allowable tensile stress taken
from the welded product values of the stress tables, and
the requirements of UW-12(d) applied.
(f) A value of E not greater than 0.80 may be used in
the formulas of this Division for joints completed by any
of the pressure welding processes given in UW-27(a),
except for electric resistance welding, provided the welding
process used is permitted by the rules in the applicable
parts of Subsection C for the material being welded. The
quality of such welds used in vessels or parts of vessels
shall be proved as follows: Test specimens shall be representative of the production welding on each vessel. They
may be removed from the shell itself or from a prolongation
of the shell including the longitudinal joint, or, in the case
of vessels not containing a longitudinal joint, from a test
plate of the same material and thickness as the vessel
and welded in accordance with the same procedure. One
reduced-section tension test and two side-bend tests shall
be made in accordance with, and shall meet the requirements of QW-150 and QW-160, Section IX.
JOINT EFFICIENCIES
Table UW-12 gives the joint efficiencies E to be used
in the formulas of this Division for joints completed by
an arc or gas welding process. Except as required by
UW-11(a)(5), a joint efficiency depends only on the type
of joint and on the degree of examination of the joint and
does not depend on the degree of examination of any other
joint. The User or his designated agent [see U-2(a)] shall
establish the type of joint and the degree of examination
when the rules of this Division do not mandate specific
requirements. Rules for determining the applicability of the
efficiencies are found in the various paragraphs covering
design formulas [for example, see UG-24(a) and UG-27].
For further guidance, see Appendix L.
(a) A value of E not greater than that given in column
(a) of Table UW-12 shall be used in the design calculations
for fully radiographed butt joints [see UW-11(a)], except
that when the requirements of UW-11(a)(5) are not met,
a value of E not greater than that given in column (b) of
Table UW-12 shall be used.
(b) A value of E not greater than that given in column
(b) of Table UW-12 shall be used in the design calculations
for spot radiographed butt welded joints [see UW-11(b)].
(c) A value of E not greater than that given in column
(c) of Table UW-12 shall be used in the design calculations
UW-13
ATTACHMENT DETAILS
(a) Definitions
th p nominal thickness of head
tp p minimum distance from outside surface of flat
head to edge of weld preparation measured as
shown in Fig. UW-13.2
ts p nominal thickness of shell
(See UG-27, UG-28, UG-32, UG-34, and other paragraphs
for additional definitions.)
(b)(1) Ellipsoidal, torispherical, and other types of
formed heads shall be attached to the shell with a butt weld,
or as illustrated in the applicable Fig. UW-13.1 sketches (a),
(b), (c), (d), and (j). The construction shown in sketch (e)
may also be used for end heads when the thickness of the
shell section of the vessel does not exceed 5⁄8 in. (16 mm)
[see also (c) below]. Limitations relative to the use of these
attachments shall be as given in the sketches and related
notes and in Table UW-12. Figure UW-13.1 sketches (f),
116
Butt joints as attained by
double-welding or by other
means which will obtain the
same quality of deposited
weld metal on the inside and
outside weld surfaces to
agree with the requirements
of UW-35. Welds using
metal backing strips which
remain in place are
excluded.
Single-welded butt joint with
backing strip other than
those included under (1)
Single-welded butt joint without use of backing strip
Double full fillet lap joint
Single full fillet lap joints with
plug welds conforming to
UW-17
(2)
(3)
(4)
(5)
Joint Description
(1)
Type
No.
117
(a) Circumferential joints [Note (4)]
for attachment of heads not over 24 in.
(600 mm) outside diameter to shells
not over 1⁄2 in. (13 mm) thick
(b) Circumferential joints for the
attachment to shells of jackets not over
5
⁄8 in. (16 mm) in nominal thickness
where the distance from the center of
the plug weld to the edge of the plate is
not less than 11⁄2 times the diameter of
the hole for the plug.
(a) Longitudinal joints not over 3⁄8 in.
(10 mm) thick
(b) Circumferential joints not over
5
⁄8 in. (16 mm) thick
NA
NA
C
NA
B&C
[Note (3)]
B
NA
NA
0.90
0.90
1.00
(a) Full
[Note (1)]
A
A, B & C
A, B, C & D
A, B & C
(a) None except as in (b) below
(b) Circumferential butt joints with
one plate offset; see UW-13(b)(4) and
Fig. UW-13.1, sketch (i)
Circumferential butt joints only, not
over 5⁄8 in. (16 mm) thick and not
over 24 in. (600 mm) outside
diameter
A, B, C & D
Joint
Category
None
Limitations
NA
NA
NA
NA
NA
0.80
0.80
0.85
(b) Spot
[Note (2)]
Degree of Radiographic Examination
TABLE UW-12
MAXIMUM ALLOWABLE JOINT EFFICIENCIES FOR ARC AND GAS WELDED JOINTS
0.50
0.50
0.55
0.55
0.60
0.65
0.65
0.70
(c)
None
2010 SECTION VIII — DIVISION 1
118
Angle joints
(8)
Design per U-2(g) for Category B and
C joints
As limited by Fig. UW-13.2 and
Fig UW-16.1
(a) For the attachment of heads convex to pressure to shells not over 5⁄8 in.
(16 mm) required thickness, only with
use of fillet weld on inside of shell; or
(b) for attachment of heads having
pressure on either side, to shells not
over 24 in. (600 mm) inside diameter
and not over 1⁄4 in. (6 mm) required
thickness with fillet weld on outside of
head flange only
Limitations
B, C & D
NA
NA
NA
A&B
C&D
[Note (5)]
NA
(a) Full
[Note (1)]
A&B
Joint
Category
NA
NA
NA
NA
(b) Spot
[Note (2)]
NOTES:
(1) See UW-12(a) and UW-51.
(2) See UW-12(b) and UW-52.
(3) For Type No. 4 Category C joint, limitation not applicable for bolted flange connections.
(4) Joints attaching hemispherical heads to shells are excluded.
(5) There is no joint efficiency E in the design formulas of this Division for Category C and D corner joints. When needed, a value of E not greater than 1.00 may be used.
GENERAL NOTES:
(a) The single factor shown for each combination of joint category and degree of radiographic examination replaces both the stress reduction
factor and the joint efficiency factor considerations previously used in this Division.
(b) E p 1.0 for butt joints in compression.
Corner joints, full penetration,
partial penetration, and/or
fillet welded
Single full fillet lap joints
without plug welds
Joint Description
(7)
(6)
Type
No.
Degree of Radiographic Examination
TABLE UW-12
MAXIMUM ALLOWABLE JOINT EFFICIENCIES FOR ARC AND GAS WELDED JOINTS (CONT’D)
NA
NA
0.45
0.45
(c)
None
2010 SECTION VIII — DIVISION 1
2010 SECTION VIII — DIVISION 1
FIG. UW-13.1 HEADS ATTACHED TO SHELLS
For ellipsoidal heads — minimum 2th
but not less than 1/2 in. (13 mm)
Tangent line
For other heads —
minimum 2th 1/2 in. (13 mm)
ts
Minimum 2ts
Minimum 1.3ts
ts
Minimum 1.3ts
th
th
1/ in. (13 mm)
2
Minimum 3th
but not less than 1 in. (25 mm)
Minimum 3th 1/2 in. (13 mm)
but not less than 1 in. (25 mm)
(a) Single Fillet Lap Weld
For ellipsoidal heads — minimum 2th
but not less than 1/2 in. (13 mm)
Tangent line
For other heads —
minimum 2th 1/2 in.
(13 mm)
Plug weld
For other heads —
minimum 2th 1/2 in. (13 mm)
ts
Tangent line
For ellipsoidal heads — minimum 2th
but not less than 1/2 in. (13 mm)
Minimum ts
ts
Minimum ts
th
d
Not less than d
Minimum ts
Minimum 4ts or 4th
whichever is less
th
Minimum 3d
Minimum 3th 1/2 in. (13 mm)
but not less than 1 in. (25 mm)
(b) Double Fillet Lap Weld
(c) Single Fillet Lap Weld With Plug Welds
GENERAL NOTE: See Table UW-12 for limitations.
119
2010 SECTION VIII — DIVISION 1
FIG. UW-13.1 HEADS ATTACHED TO SHELLS (CONT’D)
Butt weld and fillet weld, if used,
shall be designed to take shear at
11/2 times the differential pressure
than can exist.
Minimum 3th but need not
exceed 11/2 in. (38 mm)
Need not exceed 1 in. (25 mm)
Tangent line
Tangent point
2th minimum
ts
Minimum ts
1/ in. (13 mm) minimum
2
th
I.D.
th
ts2
Minimum 1.3ts
ts1
Taper optional
Butt weld
Minimum 2ts
15 deg – 20 deg
(d) Single Fillet Lap Weld
Seal or fillet weld
[see UW-13(c)(2)]
GENERAL NOTE: ts1 and ts2 may be different.
(e) Intermediate Head
ts
ts
th
ts
th
(f-1)
th
(f-2)
(g)
(h)
GENERAL NOTE: Sketches (f-1), (f-2), (g), and (h) are not permissible.
Bevel optional
See Note (1)
t1
21/2t maximum
1t minimum
See Note (1)
t
Avoid sharp break
Depth of offset = t1
As desired
11/2t minimum
NOTES:
(1) See UW-13(b)(4) for limitation when
weld bead is deposited from inside.
(2) For joints connecting hemispherical heads
to shells, the following shall apply:
(a) t or t1 = 3/8 in. (10 mm) maximum
(b) maximum difference in thickness
between t or t1 = 3/32 in. (2.5 mm);
(c) use of this figure for joints connecting
hemispherical heads to shells shall be
noted in the “Remarks” part of the Data
Report Form.
t or t1 = 5/8 maximum [see Note (2)]
(i) Butt Weld With One Plate Edge Offset
GENERAL NOTE: See Table UW-12 for limitations.
120
2010 SECTION VIII — DIVISION 1
FIG. UW-13.1 HEADS ATTACHED TO SHELLS (CONT’D)
th
3y
Thinner part
Thinner part
th
3y
Tangent line
y
1/ (t – t )
2 s
h
1/ (t – t )
2 s
h
y
Length of required
taper may include
the width of the weld
ts
ts
(k)
(j)
In all cases, the projected length of taper shall be not less than 3y.
The shell plate centerline may be on either side of the head plate centerline.
th
th
Tangent line
1/ (t – t )
2 h
s
Thinner part
3y
y
Thinner part
y
3y
1/ (t – t )
2 h
s
ts
ts
(l)
(m)
In all cases shall be not less than 3y when th exceeds ts. Minimum length of skirt is 3th but need not exceed
11/2 in. (38 mm) except when necessary to provide required length of taper.
When th is equal to or less than 1.25ts, length of skirt shall be sufficient for any required taper.
Length of required taper may include the width of the weld. The shell plate centerline may be on either side
of the head plate centerline.
GENERAL NOTE: See Table UW-12 for limitations.
121
2010 SECTION VIII — DIVISION 1
(g), and (h) are examples of attachment methods which
are not permissible.
(2) Formed heads, concave or convex to the pressure,
shall have a skirt length not less than that shown in Fig.
UW-13.1, using the applicable sketch. Heads that are fitted
inside or over a shell shall have a driving fit before welding.
(3) A tapered transition having a length not less than
three times the offset between the adjacent surfaces of
abutting sections as shown in Fig. UW-13.1 sketches (j)
and (k) shall be provided at joints between formed heads
and shells that differ in thickness by more than one-fourth
the thickness of the thinner section or by more than 1⁄8 in.
(3 mm), whichever is less. When a taper is required on
any formed head thicker than the shell and intended for
butt welded attachment [Fig. UW-13.1 sketches (l) and
(m)], the skirt shall be long enough so that the required
length of taper does not extend beyond the tangent line.
When the transition is formed by removing material from
the thicker section, the minimum thickness of that section,
after the material is removed, shall not be less than that
required by UG-23(c). When the transition is formed by
adding additional weld metal beyond what would otherwise
be the edge of the weld, such additional weld metal buildup
shall be subject to the requirements of UW-42. The centerline misalignment between shell and head shall be no
greater than one-half the difference between the actual
shell and head thickness, as illustrated in Fig. UW-13.1
sketches (j), (k), (l), and (m).
(4) Shells and heads may be attached to shells or
heads using a butt weld with one plate offset as shown in
Fig. UW-13.1 sketch (i). The weld bead may be deposited
on the inside of the vessel only when the weld is accessible
for inspection after the vessel is completed. The offset
shall be smooth and symmetrical and shall not be machined
or otherwise reduced in thickness. There shall be a uniform
force fit with the mating section at the root of the weld.
Should the offset contain a longitudinal joint, the following
shall apply:
(a) The longitudinal weld within the area of the
offset shall be ground substantially flush with the parent
metal prior to the offsetting operation.
(b) The longitudinal weld from the edge of the
plate through the offset shall be examined by the magnetic
particle method after the offsetting operation. Cracks and
cracklike defects are unacceptable and shall be repaired or
removed.
(c) As an acceptable alternative to magnetic particle examination or when magnetic particle methods are
not feasible because of the nonmagnetic character of the
weld deposit, a liquid penetrant method shall be used.
Cracks and cracklike defects are unacceptable and shall
be repaired or removed.
(5) Non-butt welded bolting flanges shall be attached
to formed heads as illustrated in Fig. 1-6.
(c)(1) Intermediate heads, without limit to thickness, of
the type shown in Fig. UW-13.1 sketch (e) may be used
for all types of vessels provided that the outside diameter
of the head skirt is a close fit inside the overlapping ends
of the adjacent length of cylinder.
(2) The butt weld and fillet weld shall be designed
to take shear based on 11⁄2 times the maximum differential
pressure that can exist. The allowable stress value for the
butt weld shall be 70% of the stress value for the vessel
material and that of the fillet 55%. The area of the butt
weld in shear is the width at the root of the weld times
the length of weld. The area of the fillet weld is the minimum leg dimension times the length of weld. The fillet
weld may be omitted if the construction precludes access
to make the weld, and the vessel is in noncorrosive service.
(d) The requirements for the attachment of welded
unstayed flat heads to shells are given in UG-34 and in (e)
and (f) hereunder.
(e) When shells, heads, or other pressure parts are
welded to a forged or rolled plate to form a corner joint,
as in Fig. UW-13.2, the joint shall meet the following
requirements [see also UG-93(d)(3)]:
(1) On the cross section through the welded joint, the
line of fusion between the weld metal and the forged or
rolled plate being attached shall be projected on planes
both parallel to and perpendicular to the surface of the
plate being attached, in order to determine the dimensions
a and b, respectively (see Fig. UW-13.2).
(2) For flange rings of bolted flanged connections,
the sum of a and b shall be not less than three times the
nominal wall thickness of the abutting pressure part.
(3) For other components, the sum a and b shall be
not less than two times the nominal wall thickness of the
abutting pressure part. Examples of such components are
flat heads, tube sheets with or without a projection having
holes for a bolted connection, and the side plates of a
rectangular vessel.
(4) Other dimensions at the joint shall be in accordance with details as shown in Fig. UW-13.2.
(5) Joint details that have a dimension through the
joint less than the thickness of the shell, head or other
pressure part, or that provide attachment eccentric thereto,
are not permissible. See Fig. UW-13.2 sketches (o), (p),
and (q).
(f) When used, the hub of a tubesheet or flat head shall
have minimum dimensions in accordance with Fig. UW13.3 and shall meet the following requirements:
(1) When the hub is integrally forged with the tubesheet or flat head, or is machined from a forging, the hub
shall have the minimum tensile strength and elongation
specified for the material, measured in the direction parallel
to the axis of the vessel. Proof of this shall be furnished
122
2010 SECTION VIII — DIVISION 1
FIG. UW-13.2 ATTACHMENT OF PRESSURE PARTS TO FLAT PLATES TO FORM A CORNER JOINT
tp
ts
tw
a
tp
tp
ts
tw
ts
a
a
a
a
(a)
a
b not less
than 2ts
tw not less than ts,
and tp not less than
the smaller of ts or
1/ in. (6 mm)
4
(b)
Backing strip
may be used
ts
b
b
b
b not less
than 2ts
(b = 0)
tw not less
than ts
ts
b not less
than 2ts
a not less than ts, and
tp not less than the
smaller of ts or
1/ in. (6 mm)
4
b not less
than 2ts
a not less than ts, and
tp not less than the
smaller of ts or
1/ in. (6 mm)
4
(c)
(d)
ts
ts
a
a1
a1
b
b
a
b not less
than 2ts
(b = 0)
(e-1)
a not less than ts
(e-2)
ts
This weld metal
may be deposited
before completing
the joint
b not less
than 2ts
(f)
a2 = a
a2
a
a
a
a
a
a
a
b not less
than 2ts (b = 0)
a1 not less than 0.5a2,
not greater than 2a2
b not less
than 2ts, b = 0
is permissible
(g)
Typical Unstayed Flat Heads, Tubesheets Without a Bolting Flange, and Side Plates of Rectangular Vessels
For unstayed flat heads, see also UG-34
c
c
c
a
b=0
Backing
strip
may be
used
ts
ts
ts
a
a
b
ts
(h)
c
c
(i)
(j)
ts
a1
a
b
This weld
metal may
be deposited
before
completing
the joint
a2
b
b = 0 is
permissible
(k)
(l)
b=0
a = a 1 a2
a1 not less
than 0.5a2
not greater
than 2a2
ts is defined in UG-34(b)
Typical Tubesheets With a Bolting Flange
GENERAL NOTES:
(a) a b not less than 2ts, c not less than 0.7ts or 1.4tr, whichever is less.
(b) ts and tr are as defined in UG-34(b).
(c) Dimension b is produced by the weld preparation and shall be verified after fit up and before welding.
123
2010 SECTION VIII — DIVISION 1
FIG. UW-13.2 ATTACHMENT OF PRESSURE PARTS TO FLAT PLATES TO FORM A CORNER JOINT (CONT’D)
(b = 0)
c
a not less than 3tn
c not less
than tn or
tx, whichever
is less
c
a
b not less than 3tn
c not less than tn or
tx, whichever is less
a
a
tn
Backing strip
may be removed Backing strip
may be used
after welding
if joint is not
welded from
both sides
tn
b
tp not less than
the smallest of
tn, tx, or 1/4 in.
(6 mm)
tp
(m)
Not welded
(o)
(p)
(q)
Typical Nonpermissible Corner Joints
(n)
Typical Bolted Flange Connections
c, tn, and tx are as defined in 2-3
FIG. UW-13.3 TYPICAL PRESSURE PARTS WITH BUTT WELDED HUBS
Tension test specimen
Tension test
specimen
e
r
ts
r
ts
e is not less than ts nor
less than the required
thickness for a flat
head or tubesheet
(a)
(b)
GENERAL NOTES:
(a) Refer to Fig. UG-34 sketch (b-2) for dimensional requirements.
(b) Not permissible if machined from rolled plate unless in accordance with Appendix 20. See UW-13(f).
(c) Tension test specimen may be located inside or outside the hub.
NOTE:
(1) h is the greater of 3⁄4 in. (19 mm) or 1.5ts, but need not exceed 2 in. (50 mm).
124
h
See Note (1)
(c)
ts
2010 SECTION VIII — DIVISION 1
FIG. UW-13.4 NOZZLE NECKS ATTACHED TO PIPING OF LESSER WALL THICKNESS
1/ in. (6 mm) min. radius
4
1/ in. min. (6 mm)
4
30 deg max.
18.5 deg max.;
14 deg min.
radius
30 deg max.
tn
[Note (1)]
t rn
18.5 deg max.;
14 deg min.
tn
[See Note (1)]
See
Note (2)
See
Note (2)
t rn
30 deg max.
t1 [See Note (3)]
18.5 deg max.;
14 deg min.
t1 [See Note (3)]
1/ in. (6 mm) min. radius
4
(a)
(b)
NOTES:
(1) As defined in UG-40.
(2) Weld bevel is shown for illustration only.
(3) t1 is not less than the greater of:
(a) 0.8tr n where
tr n = required thickness of seamless nozzle wall
(b) Minimum wall thickness of connecting pipe
by a tension test specimen (subsize if necessary) taken in
this direction and as close to the hub as practical.4
(2) When the hub is machined from plate, the requirements of Appendix 20 shall be met.
(g) When the hub of a lap joint stub end is machined
from plate with the hub length in the through thickness
direction of the plate, the requirements of Appendix 20
shall be met.
(h) In the case of nozzle necks which attach to piping
[see U-1(e)(1)(a)] of a lesser wall thickness, a tapered
transition from the weld end of the nozzle may be provided
to match the piping thickness although that thickness is
less than otherwise required by the rules of this Division.
This tapered transition shall meet the limitations as shown
in Fig. UW-13.4.
center of the hole at midlength. Defects that are completely
removed in cutting the hole shall not be considered in
judging the acceptability of the weld.
UW-14(c) In addition to meeting the radiographic
requirements of (b) above, when multiple openings meeting
the requirements given in UG-36(c)(3) are in line in a
head-to-shell or Category B or C butt welded joint, the
requirements of UG-53 shall be met or the openings shall
be reinforced in accordance with UG-37 through UG-42.
UW-14(d) Except when the adjacent butt weld satisfies
the requirement for radiography in (b) above, the edge
of openings in solid plate meeting the requirements of
UG-36(c)(3) shall not be placed closer than 1⁄2 in. (13 mm)
from the edge of a Category A, B, or C weld for material
11⁄2 in. (38 mm) thick or less.
UW-14
UW-15
OPENINGS IN OR ADJACENT TO
WELDS
WELDED CONNECTIONS
(a) Nozzles, other connections, and their reinforcements
may be attached to pressure vessels by arc or gas welding.
Sufficient welding shall be provided on either side of the
line through the center of the opening parallel to the longitudinal axis of the shell to develop the strength of the
reinforcing parts as prescribed in UG-41 through shear or
tension in the weld, whichever is applicable. The strength
of groove welds shall be based on the area subjected to
shear or to tension. The strength of fillet welds shall be
based on the area subjected to shear (computed on the
minimum leg dimension). The inside diameter of a fillet
weld shall be used in figuring its length.
UW-14(a) Any type of opening that meets the requirements for reinforcement given in UG-37 or UG-39 may
be located in a welded joint.
UW-14(b) Single openings meeting the requirements
given in UG-36(c)(3) may be located in head-to-shell or
Category B or C butt welded joints, provided the weld
meets the radiographic requirements in UW-51 for a length
equal to three times the diameter of the opening with the
4
One test specimen may represent a group of forgings provided they
are of the same design, are from the same heat of material and are forged
in the same manner.
125
2010 SECTION VIII — DIVISION 1
FIG. UW-13.5 FABRICATED LAP JOINT STUB ENDS
FOR LETHAL SERVICE
Do p outside diameter of neck or tube attached by
welding on inside of vessel shell only
G p radial clearance between hole in vessel wall
and outside diameter of nozzle neck or tube
Radius p 1⁄8 in. (3 mm) minimum blend radius
r1 p minimum inside corner radius, the lesser of 1⁄4t
or 1⁄8 in. (3 mm)
t p nominal thickness of vessel shell or head,
tn p nominal thickness of nozzle wall
tw p dimension of attachment welds (fillet, singlebevel, or single-J), measured as shown in Fig.
UW-16.1
te p thickness of reinforcing plate, as defined in
UG-40
tmin p the smaller of 3⁄4 in. (19 mm) or the thickness
of the thinner of the parts joined by a fillet,
single-bevel, or single-J weld
tc p not less than the smaller of 1⁄4 in. (6 mm) or
0.7tmin (inside corner welds may be further
limited by a lesser length of projection of the
nozzle wall beyond the inside face of the vessel wall)
t1 or t2 p not less than the smaller of 1⁄4 in. (6 mm) or
0.7tmin
Weld No. 1
Weld No. 2
3/ in. (10 mm) min.
8
(b) Strength calculations for nozzle attachment welds
for pressure loading are not required for the following:
(1) Figure UW-16.1 sketches (a), (b), (c), (d), (e), (f1), (f-2), (f-3), (f-4), (g), (x-1), (y-1), and (z-1), and all the
sketches in Figs. UHT-18.1 and UHT-18.2; see L-7.1 and
L-7.7;
(2) openings that are exempt from the reinforcement
requirements by UG-36(c)(3);
(3) openings designed in accordance with the rules
for ligaments in UG-53.
(c) The allowable stress values for groove and fillet
welds in percentages of stress values for the vessel material,
which are used with UG-41 calculations, are as follows:
(1) groove-weld tension, 74%
(2) groove-weld shear, 60%
(3) fillet-weld shear, 49%
(c) Necks Attached by a Full Penetration Weld. Necks
abutting a vessel wall shall be attached by a full penetration
groove weld. See Fig. UW-16.1 sketches (a) and (b) for
examples. Necks inserted through the vessel wall may be
attached by a full penetration groove weld. See Fig. UW16.1 sketches (c), (d), and (e). When complete joint penetration cannot be verified by visual inspection or other means
permitted in this Division, backing strips or equivalent
shall be used with full penetration welds deposited from
one side.
If additional reinforcement is required, it shall be provided as integral reinforcement as described in (1) below, or
by the addition of separate reinforcement elements (plates)
attached by welding as described in (2) below.
(1) Integral reinforcement is that reinforcement provided in the form of extended or thickened necks, thickened
shell plates, forging type inserts, or weld buildup which is
an integral part of the shell or nozzle wall and, where
required, is attached by full penetration welds. See Fig.
UW-16.1 sketches (a), (b), (c), (d), (e), (f-1), (f-2), (f-3),
(f-4), (g), (x-1), (y-1), and (z-1) for examples of nozzles
with integral reinforcement where the F factor in
Fig. UG-37 may be used.
(2) Separate reinforcement elements (plates) may be
added to the outside surface of the shell wall, the inside
surface of the shell wall, or to both surfaces of the shell
wall. When this is done, the nozzle and reinforcement is
no longer considered a nozzle with integral reinforcement
and the F factor in UG-37(a) shall be F p 1.0. Figure
UW-16.1 sketches (a-1), (a-2), and (a-3) depict various
NOTE: These values are obtained by combining the following factors:
871⁄2% for combined end and side loading, 80% for shear strength, and
the applicable joint efficiency factors.
(10)
UW-16
MINIMUM REQUIREMENTS FOR
ATTACHMENT WELDS AT
OPENINGS
(a) General
(1) The terms: nozzles, connections, reinforcements,
necks, tubes, fittings, pads, and other similar terms used in
this paragraph define essentially the same type construction
and form a Category D weld joint between the nozzle (or
other term) and the shell, head, etc., as defined in UW-3(d).
(2) The location and minimum size of attachment
welds for nozzles and other connections shall conform to
the requirements of this paragraph in addition to the
strength calculations required in UW-15.
(b) Symbols. The symbols used in this paragraph and
in Figs. UW-16.1 and UW-16.2 are defined as follows:
126
FIG. UW-16.1 SOME ACCEPTABLE TYPES OF WELDED NOZZLES AND OTHER CONNECTIONS TO SHELLS, HEADS, ETC.
2010 SECTION VIII — DIVISION 1
127
(f-1)
(f-2)
tn
r1
128
t
(i)
tn
11/4tmin.
t
t
(j)
tn
t2
t1
r1
tn
t4
t3 r1
(f-4)
t1
t2
t1 or t2 not less than
the smaller of 1/4 in. (6 mm)
or 0.7tmin.
t2
t1
t
min.
Radius
1/ in. (13 mm)
2
30 deg min.
t3
t4 0.2t
but not greater
(f-3)
than 1/4 in.
(6 mm)
3/ (19 mm)
4
Rmin.
Minimum of 11/2 t
r1
For sketches (f-1) through (f-4),
see Note (1). For sketch (f-3), see Note (2).
t
30 deg max.
45 deg max.
t
tn
3/ in. (19 mm)
4
Rmin.
3
1
tn
t
t1
Radius
r1
tc
tn
(k)
tn
t
tc
(l)
tn
1/ t
2 min.
t2
t
(h)
tc
Notes follow on last page of this Figure
t2
t1
(g)
[See Notes (1) and (2)]
t
30 deg
min.
tn
Weld to pad
tw = 0.7tmin.
FIG. UW-16.1 SOME ACCEPTABLE TYPES OF WELDED NOZZLES AND OTHER CONNECTIONS TO SHELLS, HEADS, ETC. (CONT’D)
2010 SECTION VIII — DIVISION 1
129
t
1/ t
2 min.
t
(m)
(q)
(p)
1/ t
2 min.
tw = 0.7t min.
tw = 0.7t min.
t
3tn
1/ t
2 min.
R
tc
tw = 0.7t min.
tw = 0.7t min.
tn
tn
1/ t
2 min.
1/ t
2 min.
t
t
tc
(r)
tn
(6 mm)
1/ in.
4
tw = 0.7t min.
tw = 0.7t min.
tc
tn
(n)
[See Note (2)]
tw = 0.7t min.
1/ t
2 min.
30 deg min.
Radius
tw = 0.7t min.
(s)
Weld to shell
tc
tn
tw = 0.7t min.
tn
Notes follow on last page of this Figure
t
1/ t
2 min.
(o)
[See Note (2)]
tw = 0.7t min.
t
1/ t
2 min.
30 deg min.
Radius
FIG. UW-16.1 SOME ACCEPTABLE TYPES OF WELDED NOZZLES AND OTHER CONNECTIONS TO SHELLS, HEADS, ETC. (CONT’D)
2010 SECTION VIII — DIVISION 1
tw
tn
130
(v-1)
[see Note (3)]
(v-2)
[see Note (3)]
Outside
Outside
11/4tmin.
G
G
Do
A
tn
Typical Tube Connections
tc
A
tc
(u)
Section A–A
tw
16 in. (1.5 mm)
recess
1/
tn but not less than
1/ in. (6 mm)
4
11/4tmin.
Do
Do
11/4tmin.
(w-1)
[see Note (3)]
Outside
G
(w-2)
[see Note (3)]
Outside
G
Do
11/4tmin.
Notes follow on last page of this Figure.
(When used for other than square, round, or oval headers, round off corners)
tn but not
16 in.
(1.5 mm) less than
1/ in.
recess
4
(6 mm)
(t)
1/
tc
tn
FIG. UW-16.1 SOME ACCEPTABLE TYPES OF WELDED NOZZLES AND OTHER CONNECTIONS TO SHELLS, HEADS, ETC. (CONT’D)
2010 SECTION VIII — DIVISION 1
t2
131
t2
11/4tmin.
(aa)
[See Note (4)]
tw = 0.7tmin.
t1
1/ t
2 min.
t2
t1
tc
tw [See UW-16(f)(4)]
NPS 3 (DN 80) max.
(bb)
[See Note (4)]
t1
(z-1)
(z-2)
[See Notes (1) and (4)]
tc
t1 or t2 not less than the smaller of 1/4 in. (6 mm) or 0.7tmin.
(y-1)
(y-2)
[See Notes (1) and (4)]
tc
tc
t2
NOTES:
(1) Sketches (a), (b), (c), (d), (e), (f-1) through (f-4), (g), (x-1), (y-1), and (z-1) are examples of nozzles with integral reinforcement.
(2) Where the term Radius appears, provide a 1/8 in. (3 mm) minimum blend radius.
(3) For sketches (v-1) through (w-2):
(a) For applications where there are no external loads, G = 1/8 in. (3 mm) max.
(b) With external loads:
G = 0.005 for Do 1 in. (25 mm); G = 0.010 for 1 in. (25 mm) Do 4 in. (100 mm); G = 0.015 for 4 in. (100 mm) Do 65/8 in. (170 mm).
(4) For NPS 3 (DN 80) and smaller, see exemptions in UW-16(f)(2).
t1
(x-1)
(x-2)
[See Notes (1) and (4)]
tc
Either method of attachment is satisfactory
FIG. UW-16.1 SOME ACCEPTABLE TYPES OF WELDED NOZZLES AND OTHER CONNECTIONS TO SHELLS, HEADS, ETC. (CONT’D)
2010 SECTION VIII — DIVISION 1
2010 SECTION VIII — DIVISION 1
applications of reinforcement elements added to sketch (a).
Any of these applications of reinforcement elements may
be used with necks of the types shown in Fig. UW-16.1
sketches (b), (c), (d), and (e) or any other integral reinforcement types listed in (1) above. The reinforcement plates
shall be attached by welds at the outer edge of the plate,
and at the nozzle neck periphery or inner edge of the plate
if no nozzle neck is adjacent to the plate.
(a) The weld at the outer edge of the reinforcement
plate shall be a continuous fillet weld with a minimum
throat dimension of 1⁄2tmin.
(b) The weld at the inner edge of the reinforcement
plate which does not abut a nozzle neck shall be a continuous fillet weld with a minimum throat dimension 1⁄2tmin [see
Fig. UW-16.1, sketches (a-2) and (a-3)].
(c) The weld at the inner edge of the reinforcement
plate when the reinforcement plate is full penetration
welded to the nozzle neck shall be a continuous fillet weld
with a minimum throat dimension of tc [see Fig. UW-16.1,
sketches (a-1) and (a-3)].
(d) The weld at the inner edge of the reinforcement
plate when the reinforcement plate is not full penetration
welded to the nozzle neck shall be a continuous fillet weld
with a minimum throat dimension of twp0.7tmin [see Fig.
UW-16.1, sketch (h)].
(d) Neck Attached by Fillet or Partial Penetration
Welds
(1) Necks inserted into or through the vessel wall
may be attached by fillet or partial penetration welds, one
on each face of the vessel wall. The welds may be any
desired combination of fillet, single-bevel, and single-J
welds. The dimension of t1 or t2 for each weld shall be
not less than the smaller of 1⁄4 in. (6 mm) or 0.7tmin, and
their sum shall be not less than 11⁄4tmin. See Fig. UW-16.1
sketches (i), (j), (k), and (l).
If additional reinforcement is required, it may be provided in the form of extended or thickened necks, thickened
shell plates, forgings, and /or separate reinforcement elements (plates) attached by welding. Weld requirements
shall be the same as given in (c)(2) above, except as follows. The welds attaching the neck to the vessel wall
or to the reinforcement plate shall consist of one of the
following:
(a) a single-bevel or single-J weld in the shell plate,
and a single-bevel or single-J weld in each reinforcement
plate. The dimension tw of each weld shall be not less than
0.7tmin. See Fig. UW-16.1 sketches (q) and (r).
(b) a full penetration groove weld in each reinforcement plate, and a fillet, single-bevel, or single-J weld
with a weld dimension tw not less than 0.7tmin in the shell
plate. See Fig. UW-16.1 sketch (s).
(2) Nozzle necks, flared necks, and studding outlet
type flanges may be attached by fillet welds or partial
penetration welds between the outside diameter or the
attachment and the outside surface of the shell and at the
inside of the opening in the shell. The throat dimension of
the outer attachment weld shall not be less than 1⁄2tmin. The
dimension tw of the weld at the inside of the shell cutout
shall not be less than 0.7tmin. See Fig. UW-16.1 sketches
(m), (n), (o), and (p).
(e) Necks and Tubes Up to and Including NPS 6 (DN
150) Attached From One Side Only. Necks and tubes not
exceeding NPS 6 (DN 150) may be attached from one side
only on either the outside or inside surface of the vessel.
(1) The depth of the welding groove or the throat of
the fillet weld shall be at least equal to 11⁄4tmin. The radial
clearance between the vessel hole and the nozzle outside
diameter at the unwelded side shall not exceed the tolerances given in Fig. UW-16.1 sketches (v-1), (v-2), (w-1),
and (w-2). When welded from the outside only, the neck
or tube shall extend to be at least flush to the inside surface
of the vessel wall. Such attachments shall satisfy the rules
for reinforcement of openings, except that no material in
the nozzle neck shall be counted as reinforcement.
(2) As an alternative to (1) above, when the neck or
tube is attached from the outside only, a welding groove
shall be cut into the surface to a depth of not less than tn
on the longitudinal axis of the opening. It is recommended
that a recess 1⁄16 in. (1.5 mm) deep be provided at the
bottom of the groove, in which to center the nozzle. The
dimension tw of the attachment weld shall be not less than
tn nor less than 1⁄4 in. (6 mm). See Fig. UW-16.1 sketches
(t) and (u).
(f) Standard Fittings: ASME/ANSI or Manufacturer’s
Standard. The attachment of standard fittings shall meet
the following requirements; see UW-16(g) for the attachment of bolting pads:
(1) Except as provided for in (2), (3), (4), (5), and
(6) below, fittings shall be attached by a full penetration
groove weld or by two fillet or partial penetration welds,
one on each face of the vessel wall. The minimum weld
dimensions shall be as shown in Fig. UW-16.1 sketches
(x), (y), (z), and (aa).
(2) Fittings not exceeding NPS 3 (DN 80) shown on
Fig. UW-16.1 sketches (x), (y), (z), (aa), and (bb) may be
attached by welds that are exempt from size requirements
with the following limitations:
(a) UW-15(a) requirements shall be satisfied for
UG-22 loadings.
(b) For partial penetration welds or fillet welds, t1
or t2 shall not be less than the smaller of 3⁄32 in. (2.5 mm)
or 0.7tmin.
(3)(a) Fittings not exceeding NPS 3 (DN 80), as
shown in Fig. UW-16.2, may be attached to vessels that
are not subject to rapid fluctuations in pressure by a fillet
weld deposited from the outside only without additional
reinforcement other than is inherent in the fitting and its
132
2010 SECTION VIII — DIVISION 1
(10)
TABLE UW-16.1
MINIMUM THICKNESS REQUIRED
BY UW-16(f)(3)(a)(6)
NPS
in.
mm
⁄8
⁄4
3
⁄8
1
⁄2
0.11
0.11
0.11
0.14
2.7
2.7
2.7
3.6
3
⁄4
1
11⁄4
11⁄2
0.16
0.22
0.30
0.30
4.2
5.5
7.5
7.5
2
21⁄2
3
0.31
0.37
0.38
7.9
9.5
9.5
1
1
shown in Fig. UW-16.1 illustration (bb). The groove weld
tw shall not be less than the thickness of Schedule 160 pipe
(ASME B36.10M) for the nearest equivalent pipe size.
[For fittings smaller than NPS 1⁄2 (DN 15), use Schedule
160 taken from Table 3 of ASME B16.11.]
(5) Flange-type fittings not exceeding NPS 2
(DN 50), with some acceptable types such as those shown
in Fig. UW-16.2, may be attached without additional reinforcement other than that in the fitting and its attachment
to the vessel wall. The construction satisfies the requirements of this Division without further calculation or proof
test as permitted in UG-36(c)(3) provided all of the following conditions are met:
(a) Maximum vessel wall thickness shall not
exceed 3⁄8 in. (10 mm).
(b) Maximum design pressure shall not exceed
350 psi (2.5 MPa).
(c) Minimum fillet leg tf is 3⁄32 in. (2.45 mm).
(d) The finished opening, defined as the hole in
the vessel wall, shall not exceed the outside diameter of
the nominal pipe size plus 3⁄4 in. (19 mm).
(6) Fittings conforming to Fig. UW-16.2 sketch (k)
not exceeding NPS 3 (DN 80) may be attached by a single
fillet weld on the inside of the vessel only, provided the
criteria of Fig. UW-16.1 sketch (w) and UW-16(e)(1)
are met.
(g) Bolting Pads: Manufacturer’s Standard. The attachment of standard bolting pads shall meet the following
requirements:
(1) Except as provided for in (2) and (3), bolting pads
shall be attached by a full penetration groove weld or by
two fillet or partial penetration welds, one on each face of
the vessel wall. The minimum weld dimensions shall be
as shown in Fig. UW-16.1, illustrations (p), (x), (y), (z),
and (aa).
(2) Bolting pads as shown in Fig. UW-16.3 illustrations (a) and (b) may be attached to vessels by a fillet
weld deposited from the outside only with the following
limitations:
(a) The maximum vessel wall thickness is 3⁄8 in.
(10 mm), and the bolting pad outside the diameter is not
greater than 43⁄4 in. (120 mm).
(b) The maximum size of the opening in the vessel
is limited to the following:
(1) 43⁄4 in. (120 mm) for bolting pads that are
installed through wall; see Fig. UW-16.3, illustration (a)
(2) 1⁄4 in. (6 mm) less than the bolting pad diameter for those that are attached to the outside of the vessel;
see Fig. UW-16.3, illustration (b).
(c) The attachment weld throat shall be the greatest
of the following:
(1) the minimum nozzle neck thickness required
by UG-45 for the same nominal size connection
(2) 1.0 tmin
attachment to the vessel wall provided all of the following
conditions are met:
(1) maximum vessel wall thickness of 3⁄8 in.
(10 mm);
(2) the maximum size of the opening in the vessel is limited to the outside diameter of the attached pipe
plus 3⁄4 in. (19 mm), but not greater than one-half of the
vessel inside diameter;
(3) the attachment weld throat shall be the
greater of the following:
(a) the minimum nozzle neck thickness
required by UG-45 for the same nominal size connection; or
(b) that necessary to satisfy the requirements
of UW-18 for the applicable loadings of UG-22.
(4) the typical fitting dimension tf as shown in
Fig. UW-16.2 sketch (p) shall be sufficient to accommodate
a weld leg which will provide a weld throat dimension.
(5) The openings shall meet the requirements
provided in UG-36(c)(3)(c) and (d).
(6) The minimum wall thickness shall not be
less than that shown in Table UW-16.1 for the nearest
equivalent nominal pipe size.
(b) If the opening does not meet the requirements
of (f)(3)(a)(5) or exceeds the requirements of (f)(3)(a)(2)
above or (f)(5)(d) below in any direction, or is greater than
one-half the vessel inside diameter, the part of the vessel
affected shall be subjected to a proof test as required in
UG-36(a)(2), or the opening shall be reinforced in accordance with UG-37 and the nozzle or other connection
attached, using a suitable detail in Fig. UW-16.1, if welded.
In satisfying the rules for reinforcement of openings, no
material in the nozzle neck shall be counted as reinforcement.
(4) Fittings not exceeding NPS 3 (DN 80) may be
attached by a fillet groove weld from the outside only as
133
2010 SECTION VIII — DIVISION 1
(10)
FIG. UW-16.2 SOME ACCEPTABLE TYPES OF SMALL STANDARD FITTINGS
GENERAL NOTE: See UW-16(f) for limitations.
134
2010 SECTION VIII — DIVISION 1
FIG. UW-16.2 SOME ACCEPTABLE TYPES OF SMALL STANDARD FITTINGS (CONT’D)
GENERAL NOTE: See UW-16(f) for limitations.
135
2010 SECTION VIII — DIVISION 1
FIG. UW-16.2 SOME ACCEPTABLE TYPES OF SMALL STANDARD FITTINGS (CONT’D)
GENERAL NOTE: See UW-16(f) for limitations.
FIG. UW-16.3 SOME ACCEPTABLE TYPES OF SMALL BOLTING PADS
(10)
B
A
3/ in.
8
(10 mm) max.
tf (typical)
[See UW-16(g)(2)(b)(1).]
[See UW-16(g)(2)(b)(2).]
[See UW-16(g)(2)(a).]
Maximum Opening
GENERAL NOTE: See UW-16(g)(2) for limitations.
(3) that necessary to satisfy the requirements of
UW-18 for the applicable loadings of UG-22
(d) The typical bolting pad dimension, tf, as shown
in Fig. UW-16.3, illustration (a), shall be sufficient to
accommodate a weld leg that will provide a weld throat
dimension.
(e) In satisfying the rules for reinforcement of
openings, no material in the bolting pad shall be counted
as reinforcement.
(3) If the opening exceeds the requirements of
(g)(2)(b) above, or is greater than one-half the vessel inside
diameter, the part of the vessel affected shall be subjected
to a proof test as required in UG-36(a)(2), or the opening
shall be reinforced in accordance with UG-37 and the
nozzle or other connection attached, using a suitable detail
in Fig. UW-16.1, if welded.
UW-17
PLUG WELDS
(a) Plug welds may be used in lap joints, in reinforcements around openings and in nonpressure structural
attachments. They shall be properly spaced to carry their
proportion of the load, but shall not be considered to take
more than 30% of the total load to be transmitted.
(b) Plug weld holes shall have a diameter not less than
t + 1⁄4 in. (6 mm) and not more than 2t + 1⁄4 in. (6 mm),
where t is the thickness in inches of the plate or attached
part in which the hole is made.
(c) Plug weld holes shall be completely filled with weld
metal when the thickness of the plate, or attached part, in
which the weld is made is 5⁄16 in. (8 mm) or less; for thicker
plates or attached parts the holes shall be filled to a depth of
at least half the plate thickness or 5⁄16 of the hole diameter,
136
2010 SECTION VIII — DIVISION 1
FIG. UW-19.1 TYPICAL FORMS OF WELDED STAYBOLTS
Round
anchor
block
t min.
1/ in. (3 mm)
8
t min.
t min.
(a)
(b)
2d min.
0.7t min.
0.7t min.
(c)
(d)
t min.
(f)
Round anchor
block
d
2d min.
t
t
Complete
penetration (e)
t min.
t
Complete
Complete
penetration
penetration
Diameter used to
satisfy UG-50
requirements
Diameter used to
satisfy UG-50
requirements
t = nominal thickness of the thinner stayed plate
(g)
whichever is larger, but in no case less than 5⁄16 in. (8 mm).
(d) The allowable working load on a plug weld in either
shear or tension shall be computed by the following
formula:
(h)
(c) Figures UW-13.1 and UW-13.2 show several construction details that are not permissible.
(d) Unless the sizing basis is given elsewhere in this
Division, the allowable load on fillet welds shall equal the
product of the weld area (based on minimum leg dimension), the allowable stress value in tension of the material
being welded, and a joint efficiency of 55%.
(U.S. Customary Units)
P p 0.63S (d − 1 / 4 )2
(SI Units)
P p 0.63S (d − 6)2
UW-19
where
(a) Welded-in staybolts shall meet the following
requirements:
(1) the arrangement shall substantially conform to
one of those illustrated in Fig. UW-19.1;
(2) the required thickness of the plate shall not exceed
11⁄2 in. (38 mm), but if greater than 3⁄4 in. (19 mm), the
staybolt pitch shall not exceed 20 in. (500 mm);
(3) the provisions of UG-47 and UG-49 shall be followed; and
(4) the required area of the staybolt shall be determined in accordance with the requirements in UG-50.
(b) Welded stays, substantially as shown in Fig.
UW-19.2, may be used to stay jacketed pressure vessels
provided:
(1) the pressure does not exceed 300 psi (2 MPa);
(2) the required thickness of the plate does not exceed
1
⁄2 in. (13 mm);
(3) the size of the fillet welds is not less than the
plate thickness;
d p the bottom diameter of the hole in which the weld
is made
P p total allowable working load on the plug weld
S p maximum allowable stress value for the material
in which the weld is made (see UG-23)
UW-18
WELDED STAYED CONSTRUCTION
FILLET WELDS
(a) Fillet welds may be employed as strength welds for
pressure parts within the limitations given elsewhere in
this Division. Particular care shall be taken in the layout
of joints in which fillet welds are to be used in order to
assure complete fusion at the root of the fillet.
(b) Corner or tee joints may be made with fillet welds
provided the plates are properly supported independently
of such welds, except that independent supports are not
required for joints used for the purposes enumerated in
UG-55.
137
2010 SECTION VIII — DIVISION 1
FIG. UW-19.2 USE OF PLUG AND SLOT WELDS FOR
STAYING PLATES
(3) the plain plate, if used, shall meet the requirements for braced and stayed surfaces.
(d) The welds need not be radiographed, nor need they
be postweld heat treated unless the vessel or vessel part
in which they occur is required to be postweld heat treated.
UW-20
TUBE-TO-TUBESHEET WELDS
UW-20.1 Scope. These rules provide a basis for establishing weld sizes and allowable joint loads for full strength
and partial strength tube-to-tubesheet welds.
d = 11/4 in. (32 mm) max.
UW-20.2 Definitions
UW-20.2(a) Full Strength Weld. A full strength tubeto-tubesheet weld is one in which the design strength is
equal to or greater than the axial tube strength, Ft. When
the weld in a tube-to-tubesheet joint meets the requirements
of UW-20.4, it is a full strength weld and the joint does
not require qualification by shear load testing. Such a weld
also provides tube joint leak tightness.
UW-20.2(b) Partial Strength Weld. A partial strength
weld is one in which the design strength is based on the
mechanical and thermal axial tube loads (in either direction) that are determined from the actual design conditions.
The maximum allowable axial load of this weld may be
determined in accordance with UW-20.5, Appendix A, or
UW-18(d). When the weld in a tube-to-tubesheet joint
meets the requirements of UW-20.5 or UW-18(d), it is a
partial strength weld and the joint does not require qualification by shear load testing. Such a weld also provides
tube joint leak tightness.
UW-20.2(c) Seal Weld. A tube-to-tubesheet seal weld
is one used to supplement an expanded tube joint to ensure
leak tightness. Its size has not been determined based on
axial tube loading.
Min. width
stay bar = d
2d min.
(4) the inside welds are properly inspected before the
closing plates are attached;
(5) the allowable load on the fillet welds is computed
in accordance with UW-18(d);
(6) the maximum diameter or width of the hole in
the plate does not exceed 11⁄4 in. (32 mm);
(7) the welders are qualified under the rules of Section IX;
(8) the maximum spacing of stays is determined by
the formula in UG-47(a), using C p 2.1 if either plate is
not over 7⁄16 in. (11 mm) thick, C p 2.2 if both plates are
over 7⁄16 in. (11 mm) thick.
(c) Welded stayed construction, consisting of a dimpled
or embossed plate welded to another like plate or to a plain
plate may be used, provided:
(1) the welded attachment is made by fillet welds
around holes or slots as shown in Fig. UW-19.2 or if the
thickness of the plate having the hole or slot is 3⁄16 in.
(5 mm) or less, and the hole is 1 in. (25 mm) or less in
diameter, the holes may be completely filled with weld
metal. The allowable load on the weld shall equal the
product of the thickness of the plate having the hole or
slot, the circumference or perimeter of the hole or slot, the
allowable stress value in tension of the weaker of the
materials being joined and a joint efficiency of 55%;
(2) the maximum allowable working pressure of the
dimpled or embossed components is established in accordance with the requirements of UG-101. The joint efficiency, E, used in UG-101 to calculate the MAWP of the
dimpled panel shall be taken as 0.80. This proof test may
be carried out on a representative panel. If a representative
panel is used, it shall be rectangular in shape and at least
5 pitches in each direction, but not less than 24 in. (600
mm) in either direction;
UW-20.3 Nomenclature. The symbols described
below are used for the design of tube-to-tubesheet welds.
ac p length of the combined weld legs measured parallel to the longitudinal axis of the tube at its outside
diameter
af p fillet weld leg
ag p groove weld leg
ar p minimum required length of the weld leg(s) under
consideration
do p tube outside diameter
Fd p design strength, but not greater than Ft
fd p ratio of the design strength to the tube strength
p 1.0 for full strength welds
p Fd /Ft for partial strength welds
Ff p fillet weld strength, but not greater than Ft
p 0.55af (do + 0.67af) Sw
ff p ratio of the fillet weld strength to the design
strength
p 1 − Fg / (fd Ft)
138
2010 SECTION VIII — DIVISION 1
FIG. UW-20.1 SOME ACCEPTABLE TYPES OF TUBE-TO-TUBESHEET STRENGTH WELDS
Clad material
(if present)
typical
af
ag
t
t
af
ag
do
do
(a)
(b)
ac
ac
af
af
af
af
t
ag
ag
ag
ac af
af ag
ag
do
Sp
Sa p
St p
Sw p
tp
do
ac af
af ag
ag
(c)
Fg p
p
Ft p
p
fw p
p
Lmax p
t
ag
(d)
groove weld strength, but not greater than Ft
0.85ag (do + 0.67ag) Sw
axial tube strength
t (do − t) Sa
weld strength factor
Sa /Sw
maximum allowable axial load in either direction
on the tube-to-tubesheet joint
allowable stress value as given in the applicable
part of Section II, Part D
allowable stress in tube (see S, above)
allowable stress of the material to which the tube
is welded (see S, above)
allowable stress in weld (lesser of Sa or St, above)
nominal tube thickness
UW-20.4 Full Strength Welds. Full strength welds
shown in Fig. UW-20.1 shall conform to the following
requirements:
UW-20.4(a) The size of a full strength weld shall be
determined in accordance with UW-20.6.
UW-20.4(b) The maximum allowable axial load in
either direction on a tube-to-tubesheet joint with a full
strength weld shall be determined as follows:
UW-20.4(b)(1) For loads due to pressure-induced
axial forces, LmaxpFt.
UW-20.4(b)(2) For loads due to thermally induced or
pressure plus thermally induced axial forces:
UW-20.4(b)(2)(a) LmaxpFt for welded only tubeto-tubesheet joints, where the thickness through the weld
throat is less than the nominal tube thickness t;
NOTE: For a welded tube or pipe, use the allowable stress for the
equivalent seamless product. When the allowable stress for the equivalent
seamless product is not available, divide the allowable stress of the welded
product by 0.85.
UW-20.4(b)(2)(b) Lmaxp2Ft for all other welded
tube-to-tubesheet joints.
139
2010 SECTION VIII — DIVISION 1
UW-20.5 Partial Strength Welds. Partial strength
welds shown in Fig. UW-20.1 shall conform to the following requirements:
UW-20.5(a) The size of a partial strength weld shall be
determined in accordance UW-20.6.
UW-20.5(b) The maximum allowable axial load in
either direction on a tube-to-tubesheet joint with a partial
strength weld shall be determined as follows:
UW-20.5(b)(1) For loads due to pressure-induced
axial forces, L maxpFf + Fg, but not greater than Ft.
UW-20.5(b)(2) For loads due to thermally induced or
pressure plus thermally induced axial forces:
UW-20.5(b)(2)(a) L maxpFf + Fg, but not greater
than Ft, for welded only tube-to-tubesheet joints, where
the thickness through the weld throat is less than the nominal tube thickness t;
UW-20.5(b)(2)(b) L max p2(F f + F g ), but not
greater than 2Ft, for all other welded tube-to-tubesheet
joints.
UW-20.6(d)(2) For partial strength welds, ac shall not
be less than (ar + ag).
Calculate af: af pac − ag.
UW-20.6 Weld Size Design Formulas. The size of
tube-to-tubesheet strength welds shown in Fig. UW-20.1
shall conform to the following requirements:
UW-20.6(a) For fillet welds shown in sketch (a),
ar p 冪共0.75do兲2 + 2.73t共do − t兲 fw fd − 0.75do
UW-20.6(a)(1) For full strength welds, af shall not
be less than the greater of ar or t.
UW-20.6(a)(2) For partial strength welds, af shall not
be less than ar.
UW-20.6(b) For groove welds shown in sketch (b),
ar p 冪共0.75do兲2 + 1.76t共do − t兲 fw fd − 0.75do
UW-20.6(b)(1) For full strength welds, ag shall not
be less than the greater of ar or t.
UW-20.6(b)(2) For partial strength welds, ag shall not
be less than ar.
UW-20.6(c) For combined groove and fillet welds
shown in sketch (c), where af is equal to ag,
ar p 2
冤冪共0.75d 兲
o
2
+ 1.07t共do − t兲 fw fd − 0.75do
UW-20.7 Clad Tubesheets
UW-20.7(a) Tube-to-tubesheet welds in the cladding of
either integral or weld metal overlay clad tubesheets may
be considered strength welds (full or partial), provided the
welds meet the design requirements of UW-20. In addition,
when the strength welds are to be made in the clad material
of integral clad tubesheets, the integral clad material to be
used for tubesheets shall meet the requirements in (a)(1)
and (a)(2) for any combination of clad and base materials.
The shear strength test and ultrasonic examination specified
in (a)(1) and (a)(2) are not required for weld metal overlay
clad tubesheets.
UW-20.7(a)(1) Integral clad material shall be shear
strength tested in accordance with SA-263. One shear test
shall be made on each integral clad plate or forging and
the results shall be reported on the material test report.
UW-20.7(a)(2) Integral clad material shall be ultrasonically examined for bond integrity in accordance with
SA-578, including Supplementary Requirement S1, and
shall meet the acceptance criteria given in SA-263 for
Quality Level Class 1.
UW-20.7(b) When the design calculations for clad tubesheets are based on the total thickness including the cladding, the clad material shall meet any additional
requirements specified in Part UCL.
UW-20.7(c) When tubesheets are constructed using linings, or integral cladding that does not meet the requirements of UW-20.7(a)(1) and (a)(2), the strength of the
tube-to-tubesheet joint shall not be dependent upon the
connection between the tubes and the lining or integral
cladding, as applicable.
(10)
UW-21
(10)
FLANGE TO NOZZLE NECK WELDS
UW-21(a) ASME B16.5 socket weld flanges shall be
welded to a nozzle neck using an external fillet weld. The
minimum fillet weld throat dimension shall be the lesser
of the nozzle wall thickness or 0.7 times the hub thickness
of the socket weld flange. See Fig. UW-21, illustration (4).
UW-21(b) ASME B16.5 slip-on flanges shall be welded
to a nozzle neck using an internal and an external weld.
See Fig. UW-21, illustrations (1), (2), and (3).
冥
UW-20.6(c)(1) For full strength welds, ac shall not
be less than the greater of ar or t.
UW-20.6(c)(2) For partial strength welds, ac shall not
be less than ar.
Calculate af and ag: af pac/2 and agpac/2.
UW-20.6(d) For combined groove and fillet welds
shown in sketch (d), where af is not equal to ag, ar shall
be determined as follows: Choose ag. Calculate ar:
FABRICATION
ar p 冪共0.75do兲 + 2.73t共do − t兲 fw fd ff − 0.75do
2
UW-26
UW-20.6(d)(1) For full strength welds, ac shall not
be less than the greater of (ar + ag) or t.
GENERAL
(a) The rules in the following paragraphs apply specifically to the fabrication of pressure vessels and vessel parts
140
2010 SECTION VIII — DIVISION 1
FIG. UW-21 TYPICAL DETAILS FOR SLIP-ON AND SOCKET WELDED FLANGE ATTACHMENT WELDS
xmin
xmin
xmin
xmin
xmin
xmin
xmin
xmin
1.5 mm (1/16 in.)
approximate tn
gap before
welding
The lesser of tn or
1/ in. (6 mm)
4
(1)
(2)
(3)
(4)
GENERAL NOTE: xmin pthe lesser of 1.4tn or the thickness of the hub
that are fabricated by welding and shall be used in conjunction with the general requirements for Fabrication in Subsection A, and with the specific requirements for
Fabrication in Subsection C that pertain to the class of
material used.
(b) Each Manufacturer or parts Manufacturer shall be
responsible for the quality of the welding done by his
organization and shall conduct tests not only of the welding
procedure to determine its suitability to ensure welds which
will meet the required tests, but also of the welders and
welding operators to determine their ability to apply the
procedure properly.
(c) No production welding shall be undertaken until
after the welding procedures which are to be used have
been qualified. Only welders and welding operators who
are qualified in accordance with Section IX shall be used
in production.
(d) The Manufacturer (Certificate Holder) may engage
individuals by contract or agreement for their services as
welders5 at the shop location shown on the Certificate of
Authorization and at field sites (if allowed by the Certificate
of Authorization) for the construction of pressure vessels
or vessel parts, provided all of the following conditions
are met:
(1) All Code construction shall be the responsibility
of the Manufacturer.
(2) All welding shall be performed in accordance
with the Manufacturer’s welding procedure specifications
in accordance with the requirements of Section IX.
(3) All welders shall be qualified by the Manufacturer
in accordance with the requirements of Section IX.
(4) The Manufacturer’s Quality Control System shall
include as a minimum:
5
(a) a requirement for complete and exclusive
administrative and technical supervision of all welders by
the Manufacturer;
(b) evidence of the Manufacturer’s authority to
assign and remove welders at his discretion without
involvement of any other organization;
(c) a requirement for assignment of welder identification symbols;
(d) evidence that this program has been accepted
by the Manufacturer’s Authorized Inspection Agency
which provides the inspection service.
(5) The Manufacturer shall be responsible for Code
compliance of the vessel or part, including Code Symbol
stamping and providing Data Report Forms properly executed and countersigned by the Inspector.
UW-27
WELDING PROCESSES
(a) The welding processes that may be used in the construction of vessels under this Part of this Division are
restricted as follows:
(1) arc welding processes: atomic hydrogen, electrogas, gas metal arc, gas tungsten arc, plasma arc, shielded
metal arc, stud, and submerged arc;
(2) other than arc welding processes: electron beam,
flash, electroslag, explosive,6 induction, inertia and continuous drive friction, laser beam, oxyfuel gas, resistance,
and thermit.
(b) Other than pressure inherent to the welding processes, no mechanical pressure or blows shall be applied
except as permitted for peening in UW-39.
(c) Definitions are given in Section IX which include
variations of these processes.
6
explosive welding — a solid state welding process wherein coalescence
is produced by the application of pressure by means of an explosion.
Welder includes brazer, welding operator, and brazing operator.
141
(10)
2010 SECTION VIII — DIVISION 1
UW-29
(d) Arc stud welding and resistance stud welding may
be used only for nonpressure-bearing attachments, having
a load or nonload-carrying function, except for material
listed in Table UHT-23 provided that, in the case of ferrous
materials, the heat treatment requirements of UCS-56 are
complied with and the requirements of UW-28(b) and
UW-29(a) are met prior to start of production welding.
Studs shall be limited to 1 in. (25 mm) diameter maximum
for round studs and an equivalent cross-sectional area for
studs with other shapes.
(e) The electroslag welding process may be used for
butt welds only in ferritic steels and austenitic stainless
steels of types listed in UW-5(d), provided the requirements
of UW-11(a)(6) and UW-11(d) are satisfied.
(f) The electrogas welding process may be used for butt
welds only in ferritic steels and austenitic stainless steels
of types listed in UW-5(d), provided the requirements of
UW-11(a)(6) are satisfied. When a single pass is greater
than 11⁄2 in. (38 mm) in ferritic materials, the joint shall
be given a grain refining (austenitizing) heat treatment.
UW-28
TESTS OF WELDERS AND WELDING
OPERATORS
(a) The welders and welding operators used in welding
pressure parts and in joining load-carrying nonpressure
parts (attachments) to pressure parts shall be qualified in
accordance with Section IX.
(1) The qualification test for welding operators of
machine welding equipment shall be performed on a separate test plate prior to the start of welding or on the first
workpiece.
(2) When stud welding is used to attach load-carrying
studs, a production stud weld test of each welder or welding
operator shall be performed on a separate test plate or tube
prior to the start of welding on each work shift. This weld
test shall consist of five studs, welded and tested by the
bend or torque stud weld testing procedure described in
Section IX.
(b) The welders and welding operators used in welding
nonpressure-bearing attachments, which have essentially
no load-carrying function (such as extended heat transfer
surfaces, insulation support pins, etc.), to pressure parts
shall comply with the following:
(1) When the welding process is manual, machine,
or semiautomatic, qualification in accordance with Section
IX is required.
(2) When welding is done by any automatic welding
process, performance qualification testing is not required.
(3) When stud welding is used, a production stud
weld test, appropriate to the end use application requirements, shall be specified by the Manufacturer and carried
out on a separate test plate or tube at the start of each shift.
(c) Each welder and welding operator shall be assigned
an identifying number, letter, or symbol by the manufacturer which shall be used to identify the work of that welder
or welding operator in accordance with UW-37(f).
(d) The Manufacturer shall maintain a record of the
welders and welding operators showing the date and result
of tests and the identification mark assigned to each. These
records shall be maintained in accordance with Section IX.
(e) Welding of all test coupons shall be conducted by
the Manufacturer. Testing of all test coupons shall be the
responsibility of the Manufacturer. A performance qualification test conducted by one Manufacturer shall not qualify
a welder or welding operator to do work for any other
Manufacturer except as provided in QW-300 of Section IX.
QUALIFICATION OF WELDING
PROCEDURE
(a) Each procedure of welding that is to be followed in
construction shall be recorded in detail by the manufacturer.
(b) The procedure used in welding pressure parts and
in joining load-carrying nonpressure parts, such as all permanent or temporary clips and lugs, to pressure parts shall
be qualified in accordance with Section IX.
(c) The procedure used in welding nonpressure-bearing
attachments which have essentially no load-carrying function (such as extended heat transfer surfaces, insulation
support pins, etc.), to pressure parts shall meet the following requirements.
(1) When the welding process is manual, machine,
or semiautomatic, procedure qualification is required in
accordance with Section IX.
(2) When the welding is any automatic welding process performed in accordance with a Welding Procedure
Specification (in compliance with Section IX as far as
applicable), procedure qualification testing is not required.
(d) Welding of all test coupons shall be conducted by
the Manufacturer. Testing of all test coupons shall be the
responsibility of the Manufacturer. Alternatively, AWS
Standard Welding Procedure Specifications that have been
accepted by Section IX may be used provided they meet
all other requirements of this Division. Qualification of a
welding procedure by one Manufacturer shall not qualify
that procedure for any other Manufacturer except as provided in QW-201 of Section IX.
UW-30
LOWEST PERMISSIBLE
TEMPERATURES FOR WELDING
It is recommended that no welding of any kind be done
when the temperature of the base metal is lower than 0°F
(−20°C). At temperatures between 32°F (0°C) and 0°F
(−20°C), the surface of all areas within 3 in. (75 mm) of
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2010 SECTION VIII — DIVISION 1
TABLE UW-33
the point where a weld is to be started should be heated
to a temperature at least warm to the hand [estimated to
be above 60°F (15°C)] before welding is started. It is
recommended also that no welding be done when surfaces
are wet or covered with ice, when snow is falling on the
surfaces to be welded, or during periods of high wind,
unless the welders or welding operators and the work are
properly protected.
UW-31
Customary Units
Joint Categories
Section Thickness, in.
1
Up to ⁄2, incl.
Over 1⁄2 to 3⁄4, incl.
Over 3⁄4 to 11⁄2, incl.
Over 11⁄2 to 2, incl.
Over 2
A
B, C, & D
1
1
1
1
⁄4t
⁄8 in.
1
⁄8 in.
1
⁄8 in.
Lesser of 1⁄16t or
3
⁄8 in.
CUTTING, FITTING, AND
ALIGNMENT
⁄4t
⁄4t
3
⁄16 in.
1
⁄8t
Lesser of 1⁄8t or
3
⁄4 in.
SI Units
Joint Categories
(a) When plates are shaped by oxygen or arc cutting,
the edges to be welded shall be uniform and smooth and
shall be freed of all loose scale and slag accumulations
before welding (see UG-76 and UCS-5).
(b) Plates that are being welded shall be fitted, aligned,
and retained in position during the welding operation.
(c) Bars, jacks, clamps, tack welds, or other appropriate
means may be used to hold the edges of parts in alignment.
Tack welds used to secure alignment shall either be
removed completely when they have served their purpose,
or their stopping and starting ends shall be properly prepared by grinding or other suitable means so that they may
be satisfactorily incorporated into the final weld. Tack
welds, whether removed or left in place, shall be made
using a fillet weld or butt weld procedure qualified in
accordance with Section IX. Tack welds to be left in place
shall be made by welders qualified in accordance with
Section IX, and shall be examined visually for defects, and
if found to be defective shall be removed.
Provided that the work is done under the provisions of
U-2(b), it is not necessary that a subcontractor making
such tack welds for a vessel or parts manufacturer be a
holder of a Code Certificate of Authorization. The requirements of UW-26(d) do not apply to such tack welds.
(d) The edges of butt joints shall be held during welding
so that the tolerances of UW-33 are not exceeded in the
completed joint. When fitted girth joints have deviations
exceeding the permitted tolerances, the head or shell ring,
whichever is out-of-true, shall be reformed until the errors
are within the limits specified. Where fillet welds are used,
the lapped plates shall fit closely and be kept in contact
during welding.
(e) When joining two parts by the inertia and continuous
drive friction welding processes, one of the two parts must
be held in a fixed position and the other part rotated. The
two faces to be joined must be essentially symmetrical
with respect to the axis of rotation. Some of the basic types
of applicable joints are solid round to solid round, tube to
tube, solid round to tube, solid round to plate, and tube
to plate.
Section Thickness, mm
Up to 13, incl.
Over 13 to 19, incl.
Over 19 to 38, incl.
Over 38 to 51, incl.
Over 51
UW-32
A
1
⁄4t
3 mm
3 mm
3 mm
Lesser of 1⁄16t or
10 mm
B, C, & D
1
⁄4t
⁄4t
5 mm
1
⁄8t
Lesser of 1⁄8t or
19 mm
1
CLEANING OF SURFACES TO BE
WELDED
UW-32(a) The surfaces to be welded shall be clean and
free of scale, rust, oil, grease, slag, detrimental oxides, and
other deleterious foreign material. The method and extent
of cleaning should be determined based on the material to
be welded and the contaminants to be removed. When
weld metal is to be deposited over a previously welded
surface, all slag shall be removed by a roughing tool, chisel,
chipping hammer, or other suitable means so as to prevent
inclusion of impurities in the weld metal.
UW-32(b) Cast surfaces to be welded shall be machined,
chipped, or ground to remove foundry scale and to expose
sound metal.
UW-32(c) The requirements in (a) and (b) above are
not intended to apply to any process of welding by which
proper fusion and penetration are otherwise obtained and
by which the weld remains free from defects.
UW-33
ALIGNMENT TOLERANCE
(a) Alignment of sections at edges to be butt welded
shall be such that the maximum offset is not greater than
the applicable amount for the welded joint category (see
UW-3) under consideration, as listed in Table UW-33. The
section thickness t is the nominal thickness of the thinner
section at the joint.
(b) Any offset within the allowable tolerance provided
above shall be faired at a three to one taper over the width
of the finished weld, or if necessary, by adding additional
weld metal beyond what would otherwise be the edge of
143
2010 SECTION VIII — DIVISION 1
the weld. Such additional weld metal buildup shall be
subject to the requirements of UW-42.
UW-34
(d) To assure that the weld grooves are completely filled
so that the surface of the weld metal at any point does not
fall below the surface of the adjoining base materials,9
weld metal may be added as reinforcement on each face
of the weld. The thickness of the weld reinforcement on
each face shall not exceed the following:
SPIN-HOLES
Spin-holes are permitted at the center of heads to facilitate forming. Spin-holes not greater in diameter than 23⁄8
in. (60 mm) may be closed with a full-penetration weld
using either a welded plug or weld metal. The weld and
plug shall be no thinner than the head material adjacent to
the spin-hole.
The finished weld shall be examined7 and shall meet
the acceptance requirements of Appendix 6 or Appendix
8 of this Division. Radiographic examination, if required
by UW-11(a), and additional inspections, if required by
the material specification, shall be performed.
This weld is a butt weld, but it is not categorized. It
shall not be considered in establishing the joint efficiency
of any part of the head or of the head-to-shell weld.
UW-35
Customary Units
Maximum Reinforcement, in.
Material Nominal
Thickness, in.
Less than 3⁄32
3
⁄32 to 3⁄16, incl.
Over 3⁄16 to 1⁄2, incl.
Over 1⁄2 to 1, incl.
Over 1 to 2, incl.
Over 2 to 3, incl.
Over 3 to 4, incl.
Over 4 to 5, incl.
Over 5
Category B & C
Butt Welds
3
⁄32
1
⁄8
5
⁄32
3
⁄16
1
⁄4
1
⁄4
1
⁄4
1
⁄4
5
⁄16
Other
Welds
1
⁄32
1
⁄16
3
⁄32
3
⁄32
1
⁄8
5
⁄32
7
⁄32
1
⁄4
5
⁄16
SI Units
Maximum Reinforcement, mm.
FINISHED LONGITUDINAL AND
CIRCUMFERENTIAL JOINTS
(a) Butt welded joints shall have complete penetration
and full fusion. As-welded surfaces are permitted; however,
the surface of welds shall be sufficiently free from coarse
ripples, grooves, overlaps, and abrupt ridges and valleys
to permit proper interpretation of radiographic and other
required nondestructive examinations. If there is a question
regarding the surface condition of the weld when interpreting a radiographic film, the film shall be compared to the
actual weld surface for determination of acceptability.
(b) A reduction in thickness due to the welding process
is acceptable provided all of the following conditions
are met:
(1) The reduction in thickness shall not reduce the
material of the adjoining surfaces below the minimum
required thickness at any point.
(2) The reduction in thickness shall not exceed 1⁄32
in. (1 mm) or 10% of the nominal thickness of the adjoining
surface, whichever is less.8
(c) When a single-welded butt joint is made by using
a backing strip which is left in place [Type No. (2) of
Table UW-12], the requirement for reinforcement applies
only to the side opposite the backing strip.
Material Nominal
Thickness, mm
Category B & C
Butt Welds
Other
Welds
Less than 2.4
2.4 to 4.8, incl.
Over 4.8 to 13, incl.
Over 13 to 25, incl.
Over 25 to 51, incl.
Over 51 to 76, incl.
Over 76 to 102, incl.
Over 102 to 127,
incl.
Over 127
2.4
3.2
4.0
4.8
5
6
6
6
0.8
1.6
2.4
2.4
3.2
4
6
6
8
8
UW-36
FILLET WELDS
In making fillet welds, the weld metal shall be deposited
in such a way that adequate penetration into the base metal
at the root of the weld is secured. The reduction of the
thickness of the base metal due to the welding process at
the edges of the fillet weld shall meet the same requirements
as for butt welds [see UW-35(b)].
UW-37
MISCELLANEOUS WELDING
REQUIREMENTS
(a) The reverse side of double-welded joints shall be
prepared by chipping, grinding, or melting out, so as to
secure sound metal at the base of weld metal first deposited,
before applying weld metal from the reverse side.
(b) The requirements in (a) above are not intended to
apply to any process of welding by which proper fusion
7
Examination shall be by magnetic particle or liquid penetrant methods
when the material is ferromagnetic, or by the liquid penetrant method
when the material is nonmagnetic.
8
It is not the intent of this paragraph to require measurement of
reductions in thickness due to the welding process. If a disagreement
between the Manufacturer and the Inspector exists as to the acceptability
of any reduction in thickness, the depth shall be verified by actual measurement.
9
Concavity due to the welding process on the root side of a single
welded circumferential butt weld is permitted when the resulting thickness
of the weld is at least equal to the thickness of the thinner member of
the two sections being joined and the contour of the concavity is smooth.
144
2010 SECTION VIII — DIVISION 1
and penetration are otherwise obtained and by which the
base of the weld remains free from defects.
(c) If the welding is stopped for any reason, extra care
shall be taken in restarting to get the required penetration
and fusion. For submerged arc welding, chipping out a
groove in the crater is recommended.
(d) Where single-welded joints are used, particular care
shall be taken in aligning and separating the components
to be joined so that there will be complete penetration and
fusion at the bottom of the joint for its full length.
(e) In welding plug welds, a fillet around the bottom of
the hole shall be deposited first.
(f) Welder and Welding Operator Identification
(1) Each welder and welding operator shall stamp
the identifying number, letter, or symbol assigned by the
Manufacturer, on or adjacent to and at intervals of not
more than 3 ft (1 m) along the welds which he makes in
steel plates 1⁄4 in. (6 mm) and over in thickness and in
nonferrous plates 1⁄2 in. (13 mm) and over in thickness; or
a record shall be kept by the Manufacturer of welders and
welding operators employed on each joint which shall be
available to the Inspector. For identifying welds on vessels
in which the wall thickness is less than 1⁄4 in. (6 mm) for
steel material and less than 1⁄2 in. (13 mm) for nonferrous
material, suitable stencil or other surface markings shall
be used; or a record shall be kept by the Manufacturer of
welders and welding operators employed on each joint
which shall be available to the Inspector; or a stamp may
be used provided the vessel part is not deformed and the
following additional requirements are met:
(a) for ferrous materials:
(1) the materials shall be limited to P-No. 1 Gr.
Nos. 1 and 2;
(2) the minimum nominal plate thickness shall
be 3⁄16 in. (5 mm), or the minimum nominal pipe wall
thickness shall be 0.154 in. (3.91 mm);
(3) the minimum design metal temperature shall
be no colder than −20°F (−29°C);
(b) for nonferrous materials:
(1) the materials shall be limited to aluminum
as follows: SB-209 Alloys 3003, 5083, 5454, and 6061;
SB-241 Alloys 3003, 5083, 5086, 5454, 6061, and 6063;
and SB-247 Alloys 3003, 5083, and 6061;
(2) the minimum nominal plate thickness shall
be 0.249 in. (6.32 mm), or the minimum nominal pipe
thickness shall be 0.133 in. (3.37 mm).
(2) When a multiple number of permanent nonpressure part load bearing attachment welds, nonload-bearing
welds such as stud welds, or special welds such as tubeto-tubesheet welds are made on a vessel, the Manufacturer
need not identify the welder or welding operator that
welded each individual joint provided:
(a) the Manufacturer’s Quality Control System
includes a procedure that will identify the welders or welding operators that made such welds on each vessel so
that the Inspector can verify that the welders or welding
operators were all properly qualified;
(b) the welds in each category are all of the same
type and configuration and are welded with the same welding procedure specification.
(3) Permanent identification of welders or welding
operators making tack welds that become part of the final
pressure weld is not required provided the Manufacturer’s
Quality Control System includes a procedure to permit the
Inspector to verify that such tack welds were made by
qualified welders or welding operators.
(g) The welded joint between two members joined by
the inertia and continuous drive friction welding processes
shall be a full penetration weld. Visual examination of the
as-welded flash roll of each weld shall be made as an inprocess check. The weld upset shall meet the specified
amount within ±10%. The flash shall be removed to sound
metal.
(h) Capacitor discharge welding may be used for welding temporary attachments and permanent nonstructural
attachments without postweld heat treatment, provided the
following requirements are met:
(1) A welding procedure specification shall be prepared in accordance with Section IX, insofar as possible
describing the capacitor discharge equipment, the combination of materials to be joined, and the technique of application. Qualification of the welding procedure is not required.
(2) The energy output shall be limited to 125 W-sec.
UW-38
REPAIR OF WELD DEFECTS
Defects, such as cracks, pinholes, and incomplete fusion,
detected visually or by the hydrostatic or pneumatic test
or by the examinations prescribed in UW-11 shall be
removed by mechanical means or by thermal gouging processes, after which the joint shall be rewelded [see
UW-40(e)].
UW-39
PEENING
(a) Weld metal and heat affected zones may be peened
by manual, electric, or pneumatic means when it is deemed
necessary or helpful to control distortion, to relieve residual
stresses, or to improve the quality of the weld. Peening
shall not be used on the initial (root) layer of weld metal
nor on the final (face) layer unless the weld is subsequently
postweld heat treated. In no case, however, is peening to
be performed in lieu of any postweld heat treatment
required by these rules.
(b) Controlled shot peening and other similar methods
which are intended only to enhance surface properties of
145
2010 SECTION VIII — DIVISION 1
the vessel or vessel parts shall be performed after any
nondestructive examinations and pressure tests required by
these rules.
(10)
UW-40
with insulating material, or the permanent insulation may
be installed provided it is suitable for the required temperature. In this procedure the internal pressure should be kept
as low as practicable, but shall not exceed 50% of the
maximum allowable working pressure at the highest metal
temperature expected during the postweld heat treatment
period.
(5) heating a circumferential band containing nozzles
or other welded attachments that require postweld heat
treatment in such a manner that the entire band shall be
brought up uniformly to the required temperature and held
for the specified time. Except as modified in this paragraph
below, the soak band shall extend around the entire vessel,
and shall include the nozzle or welded attachment. The
circumferential soak band width may be varied away from
the nozzle or attachment weld requiring PWHT, provided
the required soak band around the nozzle or attachment
weld is heated to the required temperature and held for the
required time. As an alternative to varying the soak band
width, the temperature within the circumferential band
away from the nozzle or attachment may be varied and
need not reach the required temperature, provided the
required soak band around the nozzle or attachment weld
is heated to the required temperature, held for the required
time, and the temperature gradient is not harmful throughout the heating and cooling cycle. The portion of the vessel
outside of the circumferential soak band shall be protected
so that the temperature gradient is not harmful. This procedure may also be used to postweld heat treat portions of
vessels after repairs.
(6) heating the circumferential joints of pipe or tubing
by any appropriate means using a soak band that extends
around the entire circumference. The portion outside the
soak band shall be protected so that the temperature gradient is not harmful. The proximity to the shell increases
thermal restraint, and the designer should provide adequate
length to permit heat treatment without harmful gradients
at the nozzle attachment or heat a full circumferential band
around the shell, including the nozzle.
(7) heating a local area around nozzles or welded
attachments in the larger radius sections of a double curvature head or a spherical shell or head in such a manner
that the area is brought up uniformly to the required temperature and held for the specified time. The soak band shall
include the nozzle or welded attachment. The soak band
shall include a circle that extends beyond the edges of the
attachment weld in all directions by a minimum of t or
2 in. (50 mm), whichever is less. The portion of the vessel
outside of the soak band shall be protected so that the
temperature gradient is not harmful.
(8) heating of other configurations. Local area heating
of other configurations such as “spots” or “bulls eye” local
heating not addressed in (a)(1) through (a)(7) above is
PROCEDURES FOR POSTWELD
HEAT TREATMENT
(a) The operation of postweld heat treatment shall be
performed in accordance with the requirements given in the
applicable Part in Subsection C using one of the following
procedures. In the procedures that follow, the soak band
is defined as the volume of metal required to meet or
exceed the minimum PWHT temperatures listed in Table
UCS-56. As a minimum, the soak band shall contain the
weld, heat affected zone, and a portion of base metal adjacent to the weld being heat treated. The minimum width
of this volume is the widest width of weld plus 1t or 2 in.
(50 mm), whichever is less, on each side or end of the
weld. The term t is the nominal thickness as defined in (f)
below. For additional detailed recommendations regarding
implementation and performance of these procedures, refer
to Welding Research Council (WRC) Bulletin 452, June
2000, “Recommended Practices for Local Heating of
Welds in Pressure Vessels.”
(1) heating the vessel as a whole in an enclosed furnace. This procedure is preferable and should be used
whenever practicable.
(2) heating the vessel in more than one heat in a
furnace, provided the overlap of the heated sections of the
vessel is at least 5 ft (1.5 m). When this procedure is used,
the portion outside of the furnace shall be shielded so that
the temperature gradient is not harmful. The cross section
where the vessel projects from the furnace shall not intersect a nozzle or other structural discontinuity.
(3) heating of shell sections and /or portions of vessels to postweld heat treat longitudinal joints or complicated welded details before joining to make the completed
vessel. When the vessel is required to be postweld heat
treated, and it is not practicable to postweld heat treat the
completed vessel as a whole or in two or more heats as
provided in (2) above, any circumferential joints not previously postweld heat treated may be thereafter locally
postweld heat treated by heating such joints by any appropriate means that will assure the required uniformity. For
such local heating, the soak band shall extend around the
full circumference. The portion outside the soak band shall
be protected so that the temperature gradient is not harmful.
This procedure may also be used to postweld heat treat
portions of new vessels after repairs.
(4) heating the vessel internally by any appropriate
means and with adequate indicating and recording temperature devices to aid in the control and maintenance of a
uniform distribution of temperature in the vessel wall. Previous to this operation, the vessel should be fully enclosed
146
2010 SECTION VIII — DIVISION 1
permitted, provided that other measures (based upon sufficiently similar, documented experience or evaluation) are
taken that consider the effect of thermal gradients, all significant structural discontinuities (such as nozzles, attachments, head to shell junctures), and any mechanical loads
which may be present during PWHT. The portion of the
vessel or component outside the soak band shall be protected so that the temperature gradient is not harmful.
(b) The temperatures and rates of heating and cooling
to be used in postweld heat treatment of vessels constructed
of materials for which postweld heat treatment may be
required are given in UCS-56, UHT-56, UNF-56, and
UHA-32.
(c) The minimum temperature for postweld heat treatment given in Tables UCS-56, UHT-56, and UHA-32, and
in UNF-56, shall be the minimum temperature of the plate
material of the shell or head of any vessel. Where more
than one pressure vessel or pressure vessel part are postweld heat treated in one furnace charge, thermocouples
shall be placed on vessels at the bottom, center, and top
of the charge, or in other zones of possible temperature
variation so that the temperature indicated shall be true
temperature for all vessels or parts in those zones.10
(d) When pressure parts of two different P-Number
Groups are joined by welding, the postweld heat treatment
shall be that specified according to either UCS-56 or
UHA-32, for the material requiring the higher postweld
heat treatment temperature.
(e) Postweld heat treatment, when required, shall be
done before the hydrostatic test and after any welded
repairs except as permitted by UCS-56(f). A preliminary
hydrostatic test to reveal leaks prior to postweld heat treatment is permissible.
(f ) The term nominal thickness as used in Tables
UCS-56, UCS-56.1, UHA-32, and UHT-56, is the thickness of the welded joint as defined below. For pressure
vessels or parts of pressure vessels being postweld heat
treated in a furnace charge, it is the greatest weld thickness
in any vessel or vessel part which has not previously been
postweld heat treated.
(1) When the welded joint connects parts of the same
thickness, using a full penetration buttweld, the nominal
thickness is the total depth of the weld exclusive of any
permitted weld reinforcement.
(2) For groove welds, the nominal thickness is the
depth of the groove.
(3) For fillet welds, the nominal thickness is the throat
dimension. If a fillet weld is used in conjunction with a
groove weld, the nominal thickness is the depth of the
groove or the throat dimension, whichever is greater.
(4) For stud welds, the nominal thickness shall be
the diameter of the stud.
(5) When a welded joint connects parts of unequal
thicknesses, the nominal thickness shall be the following:
(a) the thinner of two adjacent butt-welded parts
including head to shell connections;
(b) the thickness of the shell or the fillet weld,
whichever is greater, in connections to intermediate heads
of the type shown in Fig. UW-13.1 sketch (e);
(c) the thickness of the shell in connections to tubesheets, flat heads, covers, flanges (except for welded parts
depicted in Fig. 2-4(7), where the thickness of the weld
shall govern), or similar constructions;
(d) in Figs. UW-16.1 and UW-16.2, the thickness
of the weld across the nozzle neck or shell or head or
reinforcing pad or attachment fillet weld, whichever is the
greater;
(e) the thickness of the nozzle neck at the joint in
nozzle neck to flange connections;
(f) the thickness of the weld at the point of attachment when a nonpressure part is welded to a pressure part;
(g) the thickness of the weld in tube-to-tubesheet
connections.
The thickness of the head, shell, nozzle neck, or other parts
as used above shall be the wall thickness of the part at the
welded joint under consideration. For plate material, the
thickness as shown on the Material Test Report or material
Certificate of Compliance before forming may be used, at
the Manufacturer’s option, in lieu of measuring the wall
thickness at the welded joint.
(6) For repairs, the nominal thickness is the depth of
the repair weld.
UW-41
SECTIONING OF WELDED JOINTS
Welded joints may be examined by sectioning when
agreed to by user and Manufacturer, but this examination
shall not be considered a substitute for spot radiographic
examination. This type of examination has no effect on
the joint factors in Table UW-12. The method of closing
the hole by welding is subject to acceptance by the Inspector. Some acceptable methods are given in Appendix K.
UW-42
SURFACE WELD METAL BUILDUP
Construction in which deposits of weld metal are applied
to the surface of base metal for the purpose of:
(a) restoring the thickness of the base metal for strength
consideration; or
(b) modifying the configuration of weld joints in order
to provide the tapered transition requirements of UW-9(c)
and UW-33(b) shall be performed in accordance with the
following rules:
10
Furnace gas temperature measurement alone is not considered sufficiently accurate.
147
2010 SECTION VIII — DIVISION 1
(1) A butt welding procedure qualification in accordance with provisions of Section IX must be performed for
the thickness of weld metal deposited, prior to production
welding.
(2) All weld metal buildup must be examined over
the full surface of the deposit by either magnetic particle
examination to the requirements of Appendix 6, or by liquid
penetrant examination to the requirements of Appendix 8.
When such surface weld metal buildup is used in welded
joints which require full or spot radiographic examination,
the weld metal buildup shall be included in the examination.
UW-50
NONDESTRUCTIVE EXAMINATION
OF WELDS ON PNEUMATICALLY
TESTED VESSELS
On welded pressure vessels to be pneumatically tested
in accordance with UG-100, the full length of the following
welds shall be examined7 for the purpose of detecting
cracks:
(a) all welds around openings;
(b) all attachment welds, including welds attaching nonpressure parts to pressure parts, having a throat thickness
greater than 1⁄4 in. (6 mm).
INSPECTION AND TESTS
UW-46
GENERAL
UW-51
The rules in the following paragraphs apply specifically
to the inspection and testing of pressure vessels and vessel
parts that are fabricated by welding and shall be used in
conjunction with the general requirements for Inspection
and Tests in Subsection A, and with the specific requirements for Inspection and Tests in Subsection C that pertain
to the class of material used. [For tests on reinforcing
plates, see UG-37(g).]
UW-47
(a) All welded joints to be radiographed shall be examined in accordance with Article 2 of Section V except as
specified below.
(1) A complete set of radiographs and records, as
described in Article 2 of Section V, for each vessel or vessel
part shall be retained by the Manufacturer, as follows:
(a) films until the Manufacturer’s Data Report has
been signed by the Inspector;
(b) records as required by this Division (10-13).
(2) A written radiographic examination procedure is
not required. Demonstration of density and penetrameter
image requirements on production or technique radiographs shall be considered satisfactory evidence of compliance with Article 2 of Section V.
(3) The requirements of T-274.2 of Article 2 of Section V are to be used only as a guide. Final acceptance of
radiographs shall be based on the ability to see the prescribed penetrameter image and the specified hole or the
designated wire of a wire penetrameter.
(b) Indications shown on the radiographs of welds and
characterized as imperfections are unacceptable under the
following conditions and shall be repaired as provided in
UW-38, and the repair radiographed to UW-51 or, at the
option of the Manufacturer, ultrasonically examined in
accordance with the method described in Appendix 12
and the standards specified in this paragraph, provided the
defect has been confirmed by the ultrasonic examination
to the satisfaction of the Authorized Inspector prior to
making the repair. For material thicknesses in excess of 1
in. (25 mm), the concurrence of the user shall be obtained.
This ultrasonic examination shall be noted under remarks
on the Manufacturer’s Data Report Form:
(1) any indication characterized as a crack or zone
of incomplete fusion or penetration;
CHECK OF WELDING PROCEDURE
The Inspector shall assure himself that the welding procedure employed in the construction of a vessel has been
qualified under the provisions of Section IX. The Manufacturer shall submit evidence to the Inspector that the requirements have been met.
UW-48
CHECK OF WELDER AND WELDING
OPERATOR QUALIFICATIONS
(a) The Manufacturer shall certify that the welding on
a vessel has been done only by welders and welding operators who have been qualified under the requirements of
Section IX and the Inspector shall assure himself that only
qualified welders and welding operators have been used.
(b) The Manufacturer shall make available to the
Inspector the record of the qualification tests of each welder
and welding operator. The Inspector shall have the right
at any time to call for and witness tests of the welding
procedure or of the ability of any welder and welding
operator.
UW-49
RADIOGRAPHIC EXAMINATION OF
WELDED JOINTS
CHECK OF POSTWELD HEAT
TREATMENT PRACTICE
The Inspector shall satisfy himself that all postweld heat
treatment has been correctly performed and that the temperature readings conform to the requirements.
148
2010 SECTION VIII — DIVISION 1
(2) any other elongated indication on the radiograph
which has length greater than:
(a) 1⁄4 in. (6 mm) for t up to 3⁄4 in. (19 mm)
(b) 1⁄3t for t from 3⁄4 in. (19 mm) to 21⁄4 in. (57 mm)
(c) 3⁄4 in. (19 mm) for t over 21⁄4 in. (57 mm)
of a double-welded butt joint, one spot may represent the
work of all welders or welding operators.
(3) Each spot examination shall be made as soon as
practicable after completion of the increment of weld to
be examined. The location of the spot shall be chosen by
the Inspector after completion of the increment of welding
to be examined, except that when the Inspector has been
notified in advance and cannot be present or otherwise
make the selection, the Manufacturer may exercise his own
judgment in selecting the spots.
(4) Radiographs required at specific locations to satisfy the rules of other paragraphs, such as UW-9(d),
UW-11(a)(5)(b), and UW-14(b), shall not be used to satisfy
the requirements for spot radiography.
(c) Standards for Spot Radiographic Examination. Spot
examination by radiography shall be made in accordance
with the technique prescribed in UW-51(a). The minimum
length of spot radiograph shall be 6 in. Spot radiographs
may be retained or be discarded by the Manufacturer after
acceptance of the vessel by the Inspector. The acceptability
of welds examined by spot radiography shall be judged by
the following standards:
(1) Welds in which indications are characterized as
cracks or zones of incomplete fusion or penetration shall
be unacceptable.
(2) Welds having indications characterized as slag
inclusions or cavities are unacceptable when the indication
length exceeds 2⁄3 t, where t is defined as shown in
UW-51(b)(2). For all thicknesses, indications less than
1
⁄4 in. (6 mm) are acceptable, and indications greater than
3
⁄4 in. (19 mm) are unacceptable. Multiple aligned indications meeting these acceptance criteria are acceptable when
the sum of their longest dimensions indications does not
exceed t within a length of 6t (or proportionally for radiographs shorter than 6t), and when the longest length L for
each indication is separated by a distance not less than 3L
from adjacent indications.
(3) Rounded indications are not a factor in the acceptability of welds not required to be fully radiographed.
(d) Evaluation and Retests
(1) When a spot, radiographed as required in (b)(1)
or (b)(2) above, is acceptable in accordance with (c)(1)
and (c)(2) above, the entire weld increment represented by
this radiograph is acceptable.
(2) When a spot, radiographed as required in (b)(1)
or (b)(2) above, has been examined and the radiograph
discloses welding which does not comply with the minimum quality requirements of (c)(1) or (c)(2) above, two
additional spots shall be radiographically examined in the
same weld increment at locations away from the original
spot. The locations of these additional spots shall be determined by the Inspector or fabricator as provided for the
original spot examination in (b)(3) above.
where
t p the thickness of the weld excluding any allowable
reinforcement. For a butt weld joining two members having different thicknesses at the weld, t
is the thinner of these two thicknesses. If a full
penetration weld includes a fillet weld, the thickness of the throat of the fillet shall be included in t.
(3) any group of aligned indications that have an
aggregate length greater than t in a length of 12t, except
when the distance between the successive imperfections
exceeds 6L where L is the length of the longest imperfection
in the group;
(4) rounded indications in excess of that specified by
the acceptance standards given in Appendix 4.
UW-52
SPOT EXAMINATION OF WELDED
JOINTS
NOTE: Spot radiographing of a welded joint is recognized as an effective
inspection tool. The spot radiography rules are also considered to be an
aid to quality control. Spot radiographs made directly after a welder or
an operator has completed a unit of weld proves that the work is or is
not being done in accordance with a satisfactory procedure. If the work
is unsatisfactory, corrective steps can then be taken to improve the welding
in the subsequent units, which unquestionably will improve the weld
quality.
Spot radiography in accordance with these rules will not ensure a
fabrication product of predetermined quality level throughout. It must be
realized that an accepted vessel under these spot radiography rules may
still contain defects which might be disclosed on further examination. If
all radiographically disclosed weld defects must be eliminated from a
vessel, then 100% radiography must be employed.
(a) Butt welded joints which are to be spot radiographed
shall be examined locally as provided herein.
(b) Minimum Extent of Spot Radiographic Examination
(1) One spot shall be examined on each vessel for
each 50 ft (15 m) increment of weld or fraction thereof
for which a joint efficiency from column (b) of Table UW12 is selected. However, for identical vessels or parts, each
with less than 50 ft (15 m) of weld for which a joint
efficiency from column (b) of Table UW-12 is selected,
50 ft (15 m) increments of weld may be represented by
one spot examination.
(2) For each increment of weld to be examined, a
sufficient number of spot radiographs shall be taken to
examine the welding of each welder or welding operator.
Under conditions where two or more welders or welding
operators make weld layers in a joint, or on the two sides
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2010 SECTION VIII — DIVISION 1
this Division. SNT-TC-1A11 or CP-18911 shall be used as
a guideline for employers to establish their written practice.
National or international Central Certification Programs,
such as the ASNT Central Certification Program (ACCP),11
may be used to fulfill the examination and demonstration
requirements of the employer’s written practice. Provisions
for training, experience, qualification, and certification of
NDE personnel shall be described in the Manufacturer’s
quality control system.
(b) NDE personnel shall be qualified by examination.
Qualification of NDE Level III personnel certified prior
to the 2004 Edition of this Division may be based on
demonstrated ability, achievement, education, and experience. Such qualification shall be specifically addressed
in the written practice. When NDE personnel have been
certified in accordance with a written practice based on an
edition of SNT TC-1A or CP-189 referenced in Table U-3,
their certification shall be valid until their next scheduled
recertification.
(c) Recertification shall be in accordance with the
employer’s written practice based on the edition of
SNT-TC-1A or CP-189 referenced in Table U-3. Recertification may be based on evidence of continued satisfactory
performance or by reexamination(s) deemed necessary by
the employer.
(a) If the two additional spots examined show
welding which meets the minimum quality requirements
of (c)(1) and (c)(2) above, the entire weld increment represented by the three radiographs is acceptable provided the
defects disclosed by the first of the three radiographs are
removed and the area repaired by welding. The weld
repaired area shall be radiographically examined in accordance with the foregoing requirements of UW-52.
(b) If either of the two additional spots examined
shows welding which does not comply with the minimum
quality requirements of (c)(1) or (c)(2) above, the entire
increment of weld represented shall be rejected. The entire
rejected weld shall be removed and the joint shall be
rewelded or, at the fabricator’s option, the entire increment
of weld represented shall be completely radiographed and
only defects need be corrected.
(c) Repair welding shall be performed using a qualified procedure and in a manner acceptable to the Inspector.
The rewelded joint, or the weld repaired areas, shall be
spot radiographically examined at one location in accordance with the foregoing requirements of UW-52.
UW-53
TECHNIQUE FOR ULTRASONIC
EXAMINATION OF WELDED JOINTS
Ultrasonic examination of welded joints when required
or permitted by other paragraphs of this Division shall be
performed in accordance with Appendix 12 and shall be
evaluated to the acceptance standards specified in Appendix 12. The written examination procedure shall be available to the Inspector and shall be proven by actual
demonstration to the satisfaction of the Inspector to be
capable of detecting and locating imperfections described
in this Division.
MARKING AND REPORTS
UW-60
GENERAL
The provisions for marking and reports, UG-115 through
UG-120, shall apply without supplement to welded pressure vessels.
PRESSURE RELIEF DEVICES
UW-54
UW-65
QUALIFICATION OF
NONDESTRUCTIVE EXAMINATION
PERSONNEL
GENERAL
The provisions for pressure relief devices, UG-125
through UG-136, shall apply without supplement to welded
pressure vessels.
(a) The Manufacturer shall be responsible for assuring
that nondestructive examination (NDE) personnel have
been qualified and certified in accordance with their
employer’s written practice prior to performing or evaluating radiographic or ultrasonic examinations required by
11
Recommended Practice No. SNT-TC-1A, Personnel Qualification
and Certification in Nondestructive Testing, ACCP, ASNT Central Certification Program, and CP-189 are published by the American Society
for Nondestructive Testing, Inc., 1711 Arlingate Plaza, Caller #28518,
Columbus, Ohio 43228-0518.
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2010 SECTION VIII — DIVISION 1
PART UF
REQUIREMENTS FOR PRESSURE VESSELS
FABRICATED BY FORGING
made at the minimum allowable temperature in accordance
with Part UHT of this Division, except in no case shall
the test temperature be higher than −20°F (−29°C). Certification is required. An ultrasonic examination shall be made
in accordance with UF-55.
GENERAL
UF-1
SCOPE
The rules in Part UF are applicable to forged pressure
vessels without longitudinal joints, including their component parts that are fabricated of carbon and low alloy steels
or of high alloy steels within the limitations of Part UHA.
These rules shall be used in conjunction with the applicable
requirements in Subsection A, and with the specific requirements in Subsection C that pertain to the respective classes
of all materials used.
UF-6
All materials subject to stress due to pressure shall conform to one of the specifications given in Section II and
limited to those listed in Table UCS-23 and UHA-23 for
forgings or to plates, and seamless pipe and tube when
such material is further processed by a forging operation.
MATERIALS
UF-5
FORGINGS
GENERAL
UF-7
(a) Materials used in the construction of forged pressure
vessels shall comply with the requirements for materials
given in UG-4 through UG-14, except as specifically limited or extended in (b) and (c) below, and in UF-6.
(b) The heat analysis of forgings to be fabricated by
welding shall not exceed carbon 0.35%. However, when
the welding involves only minor nonpressure attachments
as limited in UF-32, seal welding of threaded connections
as permitted in UF-43, or repairs as limited by UF-37, the
carbon content shall not exceed 0.50% by heat analysis.
When by heat analysis the carbon analysis exceeds 0.50%
no welding is permitted.
(c) This part contains special requirements applicable
to SA-372 materials subjected to liquid quench and temper
heat treatment. Such special requirements do not apply to
austenitic materials or to materials not exceeding 95 ksi
(655 MPa) specified minimum tensile strength. SA-372
materials may be subjected to accelerated cooling or may
be quenched and tempered to attain their specified minimum properties provided:
(1) after heat treatment, inspection for injurious
defects shall be performed according to UF-31(b)(1)(a);
(2) tensile strength shall not be greater than 20,000 psi
(140 MPa) above their specified minimum tensile strength.
(d) For vessels constructed of SA-372 Grade J, Class
110 or Grade L material, transverse impact tests shall be
FORGED STEEL ROLLS USED FOR
CORRUGATING PAPER
MACHINERY
Materials and rules of construction to be applied in the
manufacture of forged steel corrugating and pressure rolls
used in machinery for producing corrugated paper are covered in SA-649 in Section II, Part A.
DESIGN
UF-12
GENERAL
The rules in the following paragraphs apply specifically
to vessels or main sections of vessels that are forged from
ingots, slabs, billets, plate, pipe, or tubes, and shall be
used to supplement the requirements for design which are
applicable, as given in UG-16 through UG-55, and those
given in UCS-16 through UCS-67, and UHA-20 through
UHA-34. Sections of vessels may be joined by any method
permitted in the several parts of this Division except as
limited in UF-5(b) and UF-5(c).
Vessels constructed of SA-372 Grade A, B, C, or D;
Grade E, Class 65 or 70; Grade F, Class 70; Grade G,
Class 70; Grade H, Class 70; Grade J, Class 65, 70, or
110; Grade L; or Grade M, Class A or B must be of
streamlined design, and stress raisers, such as abrupt
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2010 SECTION VIII — DIVISION 1
changes in section, shall be minimized. Openings in vessels
constructed of liquid quenched and tempered materials,
other than austenitic steel, shall be reinforced in accordance
with UG-37; UG-36(c)(3) shall not apply.
The nominal wall thickness of the cylindrical shell of
vessels constructed of SA-372 Grade J, Class 110 shall
not exceed 2 in. (50 mm).
UF-13
the forging may be certified for a lower pressure in the
formula:
Reduced pressure P ′ p P
and in which
Sb p
HEAD DESIGN
(a) The minimum required thickness of forged heads
shall be computed using the formulas of UG-32. When
heads are made separate from the body forging they may
be attached by any method permitted in the several parts
of this Division except as limited in UF-5(b) and UF-5(c).
(b) The juncture of a forged conical head with the body
shall be a knuckle, the inside radius of which shall be not
less than 6% of the internal diameter of the vessel. The
thickness at the knuckle shall be not less than that of the
cylinder and shall be faired into that of the head at the
base of the cone.
(c) Except for the 3t requirements in UG-32( j) the
design of the head shall comply with the applicable provisions of UG-32, UG-33, UG-34, and 1-6.
UF-25
D1, D2 p the inside diameters maximum and minimum,
respectively, as measured for the critical section, and for one additional section in each
direction therefrom at a distance not exceeding
0.2D2. The average of the three readings for
D1 and D2 , respectively, shall be inserted in
the formula.
E p modulus of elasticity of material at design temperature. The modulus of elasticity shall be
taken from the applicable Table TM in Section
II, Part D. When a material is not listed in the
TM tables, the requirements of U-2(g) shall be
applied.
P p maximum allowable working pressure for
forging meeting the requirements of (a)
Ra p average radius to middle of shell wall at critical
section
p 1⁄4 (D1 + D2) + t /2
R1 p average inside radius at critical section
p 1⁄4 (D1 + D2)
S p design stress value, psi (kPa), at metal service
temperature
Sb p bending stress at metal service temperature
t p the average (mean) thickness
CORROSION ALLOWANCE
FABRICATION
GENERAL
The rules in the following paragraphs apply specifically
to forged vessels, main sections of vessels and other vessel
parts, and shall be used to supplement the applicable
requirements for fabrication given in UG-75 through
UG-84 and UCS-79. For high alloy steel forged vessels,
the applicable paragraphs of Part UHA shall also apply.
NOTES:
(1) Use P ′pP when Sb is less than 0.25S.
(2) In all measurements, correct for corrosion allowance if specified.
UF-28
UF-27
1.5 PR1 t (D1 − D2 )
P
t3 + 3
R R2
E 1 a
where
(a) Provision shall be made for corrosion in accordance
with the requirements in UG-25.
UF-26
冢 冣
1.25
Sb
+1
S
TOLERANCES ON BODY FORGINGS
METHODS OF FORMING FORGED
HEADS
Forged heads shall be made either by closing in extensions of the body of such shape and dimensions as may
be required to produce the final form desired, or by separate
forgings [see UF-13(a)].
(a) The inner surface of the body shall be true-to-round
to the degree that the maximum difference between any
two diameters at 90 deg to each other, determined for any
critical cross section, does not exceed 1% of the mean
diameter at that section. Chip marks and minor depressions
in the inner surface may be filled by welding to meet these
tolerances when the welding is done as permitted in UF-32.
(b) If out-of-roundness exceeds the limit in (a) and the
condition cannot be corrected, the forging shall be rejected
except that if the out-of-roundness does not exceed 3%,
UF-29
TOLERANCE ON FORGED HEADS
Forged heads shall be as true as it is practicable to make
them to the shape shown on the design drawings. Any
deviations therefrom shall merge smoothly into the general
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2010 SECTION VIII — DIVISION 1
shape of the head and shall not evidence a decrease of
strength for the sections as required by the formulas for
design.
UF-30
than 10% below, nor more than 25% above the number
obtained by dividing 500 into the specified minimum tensile strength of the material, and the highest average hardness number shall not exceed the lowest average value on
an individual vessel by more than 40. Reheat treatment is
permitted.
LOCALIZED THIN AREAS
Forgings are permitted to have small areas thinner than
required if the adjacent areas surrounding each have sufficient thickness to provide the necessary reinforcement
according to the rules for reinforcement in UG-40.
UF-31
NOTE: Other hardness testing methods may be used and converted to
Brinell numbers by means of the Table in ASTM E 140.
(c) For vessels which are integrally forged, having
an overall length less than 5 ft (1.5 m) and a nominal
thickness not exceeding 1⁄2 in. (13 mm), the requirements
of (b) above may be modified by taking a minimum of
two hardness readings at each end of the vessel. These
four hardness readings shall satisfy the requirements of (b)
above as if the four hardnesses were applicable to one
section.
(d) In the case of austenitic steels, the heat treatment procedures followed shall be in accordance with
UHA-32.
(c) Nonheat-Treated Material. Postweld heat treatment
of vessels fabricated by welding of forged parts not requiring heat treatment shall meet with the requirements of
UCS-56.
HEAT TREATMENT
(a) Normalized or Annealed Material
(1) After all forging is completed, each vessel or
forged part fabricated without welding shall be heat treated
in accordance with the applicable material specification.
When defects are repaired by welding, subsequent heat
treatment may be necessary in accordance with UF-37(b).
(2) Vessels fabricated by welding of forged parts
requiring heat treatment shall be heat treated in accordance
with the applicable material specification as follows:
(a) after all welding is completed; or
(b) prior to welding, followed by postweld heat
treatment of the finished weld in accordance with UW-40;
(c) when the welding involves only minor nonpressure attachments to vessels having carbon content
exceeding 0.35% but not exceeding 0.50% by ladle analysis, requirements of UF-32(b) shall govern.
(b) Liquid Quenched Material
(1) Vessels fabricated from SA-372 forging material
to be liquid quenched and tempered shall be subjected to
this heat treatment in accordance with the applicable material specifications after the completion of all forging, welding of nonpressure attachments as permitted by UF-32,
and repair welding as limited by UF-37. Seal welding
of threaded connections, as permitted in UF-43, may be
performed either before or after this heat treatment.
(a) After final heat treatment, such vessels shall be
examined for the presence of cracks on the outside surface
of the shell portion and on the inside surface where practicable. This examination shall be made by liquid penetrant
when the material is nonmagnetic and by liquid penetrant
or magnetic particle examination when the material is ferromagnetic.
(b) After final heat treatment, liquid quenched and
tempered vessels, except those made of austenitic steels
and except as provided in (c) below, shall be subjected to
Brinell hardness tests at 5 ft (1.5 m) intervals with a minimum of four readings at each of not less than three different
sections representing approximately the center and each
end of the heat treated shell. The average of the individual
Brinell hardness numbers at each section shall be not less
UF-32
WELDING FOR FABRICATION
(a) All welding used in connection with the fabrication
of forged vessels or components shall comply with the
applicable requirements of Parts UW, UCS, and UHA and
UF-5(b) except as modified in (b) and (c) below. Procedure
qualification in accordance with Section IX shall be performed with the heat treatment condition of the base metal
and weld metal as in UF-31 as contemplated for the
actual work.
(b) When the carbon content of the material exceeds
0.35% by ladle analysis, the vessel or part shall be fabricated without welding of any kind, except for repairs [see
UF-37(b)], for seal welding of threaded connections as
permitted in UF-43, and for minor nonpressure attachments. Minor nonpressure attachments shall be joined by
fillet welds of not over 1⁄4 in. (6 mm) throat dimensions.
Such welding shall be allowed under the following conditions:
(1) The suitability of the electrode and procedure
shall be established by making a groove weld specimen
as shown in QW-461.2 of Section IX in material of the
same analysis and of thickness in conformance with
QW-451. The specimen before welding shall be in the
same condition of heat treatment as the work it represents,
and after welding the specimen shall be subjected to heat
treatment equivalent to that contemplated for the work.
Tensile and bend tests, as shown in QW-462.1,
QW-462.2(a) and QW-462.3(a), shall be made. These tests
153
2010 SECTION VIII — DIVISION 1
shall meet the requirements of QW-150 and QW-160 of
Section IX. The radius of the mandrel used in the guided
bend test shall be as follows:
Specimen
Thickness
3
⁄8
in. (10 mm)
t
Radius of
Mandrel B1
Radius of
Die D1
11⁄2 in. (38 mm)
31⁄3t
111⁄16 in. (42 mm)
41⁄3t + 1⁄16 in. (1.5 mm)
(3) One face of each cross section shall be smoothed
and etched with suitable etchant (see QW-470) to give a
clear definition of the weld metal and heat affected zone.
Visual examination of the cross sections of the weld metal
and heat affected zone shall show complete fusion and
freedom from cracks.
(4) All production welding shall be done in accordance with the procedure qualification of (c)(1) above,
including the preheat and the electrode of the same classification as that specified in the procedure, and with welders
qualified using that procedure.
(5) Seal welding of threaded connections may be performed either before or after final heat treatment.
(6) The finished weld shall be examined by liquid
penetrant or magnetic particle examination using the prod
method.
NOTE:
(1) Corresponds to dimensions B and D in QW-466.1 in Section IX,
and other dimensions to be in proportion.
Any cutting and gouging processes used in the repair work
shall be included as part of the procedure qualification.
(2) Welders shall be qualified for fillet welding specified by making and testing a specimen in accordance with
QW-462.4(b) and QW-180 of Section IX. Welders shall
be qualified for repair welding by making a test plate
in accordance with QW-461.3 from which the bend tests
outlined in QW-452 shall be made. The electrode used in
making these tests shall be of the same classification number as that specified in the procedure. The material for
these tests can be carbon steel plate or pipe provided the
test specimens are preheated, welded and postheated in
accordance with the procedure specification for the type
of electrode involved.
(3) The finished weld shall be postweld heat treated or
given a further heat treatment as required by the applicable
material specification. The types of welding permitted in
UF-32(b) shall be performed prior to final heat treatment
except for seal welding of threaded openings which may
be performed either before or after final heat treatment.
(4) The finished welds shall be examined after postweld heat treatment by liquid penetrant when the material
is nonmagnetic and by liquid penetrant or magnetic particle
examination using the prod method when the material is
ferromagnetic.
(c) The following requirements shall be used to qualify
welding procedure and welder performance for seal welding of threaded connections in seamless forged pressure
vessels of SA-372 Grades A, B, C, D, E, F, G, H, and J
materials:
(1) The suitability of the welding procedure, including electrode, and the welder performance shall be established by making a seal weld in the welding position to
be used for the actual work and in a full-size prototype of
the vessel neck, including at least some portion of the
integrally forged head, conforming to the requirements of
UF-43 and the same geometry, thickness, vessel material
type, threaded-plug material type, and heat treatment as
that for the production vessel it represents.
(2) The seal weld in the prototype at the threaded
connection of the neck and plug shall be cross sectioned
to provide four macro-test specimens taken 90 deg apart.
UF-37
REPAIR OF DEFECTS IN MATERIAL
(a) Surface defects, such as chip marks, blemishes, or
other irregularities, shall be removed by grinding or
machining and the surface exposed shall be blended
smoothly into the adjacent area where sufficient wall thickness permits thin areas in compliance with the requirements
of UF-30.
(b) Thinning to remove imperfections beyond those permitted in UF-30 may be repaired by welding only after
acceptance by the Inspector. Defects shall be removed to
sound metal as shown by acid etch or any other suitable
method of examination. The welding shall be as outlined
below.
(1) Material Having Carbon Content of 0.35% or
Less (by Ladle Analysis)
(a) The welding procedure and welders shall be
qualified in accordance with Section IX.
(b) Postweld heat treatment after welding shall be
governed as follows.
(1) All welding shall be postweld heat treated
if UCS-56 requires postweld heat treatment, for all thicknesses of material of the analysis being used.
(2) Fillet welds need not be postweld heat
treated unless required by (1) above or unless the fillet
welds exceed the limits given in UCS-56.
(3) Repair welding shall be postweld heat treated
when required by (b)(1)(b)(1) above or if it exceeds 6 sq
in. (4 000 mm2) at any spot or if the maximum depth
exceeds 1⁄4 in. (6 mm).
(c) Repair welding shall be radiographed if the
maximum depth exceeds 3⁄8 in. (10 mm). Repair welds 3⁄8
in. (10 mm) and under in depth which exceed 6 sq in.
(4 000 mm2) at any spot and those made in materials requiring postweld heat treatment shall be examined by radiographing, magnetic particle or liquid penetrant
154
2010 SECTION VIII — DIVISION 1
examination, or any alternative method suitable for revealing cracks.
(d) For liquid quenched and tempered steels, other
than austenitic steels, welding repairs shall be in accordance with UF-37(b)(3).
(2) Material Having Carbon Content Over 0.35% (by
Ladle Analysis)
(a) Welding repairs shall conform with UF-32(b)
except that if the maximum weld depth exceeds 1⁄4 in.
(6 mm), radiography, in addition to magnetic particle or
liquid penetrant examination, shall be used.
(b) For liquid quenched and tempered steels, other
than austenitic steel, welding repair shall be in accordance
with (b)(3) below.
(3) Welding repairs of materials which are to be or
have been liquid quenched and tempered, regardless of
depth or area of repairs shall have the repaired area radiographed and examined by magnetic particle or liquid penetrant examination.
UF-38
the applicable requirements for inspection and tests given
in UG-90 through UG-102. All forged vessels shall be
examined as manufacture proceeds, to assure freedom from
loose scale, gouges or grooves, and cracks or seams that
are visible. After fabrication has passed the machining
stage, the vessel body shall be measured at suitable intervals along its length to get a record of variations in wall
thickness, and the nozzles for connecting piping and other
important details shall be checked for conformity to the
design dimensions.
UF-46
Surfaces which are not to be machined shall be carefully
inspected for visible defects such as seams, laps, or folds.
On surfaces to be machined the inspection shall be made
after machining. Regions from which defective material
has been removed shall be inspected after removal and
again after any necessary repair.
REPAIR OF WELD DEFECTS
UF-47
The repair of welds of forgings having carbon content
not exceeding 0.35% by ladle analysis shall follow the
requirements of UW-38.
UF-43
PARTS FORGING
(a) When welding is used in the fabrication of parts
forgings completed elsewhere, the parts forging manufacturer shall furnish a Form U-2 Partial Data Report.
(b) All parts forgings completed elsewhere shall be
marked with the manufacturer’s name and the forging identification, including material designation. Should identifying marks be obliterated in the fabrication process, and
for small parts, other means of identification shall be used.
The forging manufacturer shall furnish reports of chemical
and mechanical properties of the material and certification
that each forging conforms to all requirements of Part UF.
(c) Parts forgings furnished as material for which parts
Data Reports are not required need not be inspected at the
plant of the forging manufacturer, but the manufacturer
shall furnish a report of the extent and location of any
repairs together with certification that they were made in
accordance with all other requirements of UF-37 and
UF-38. If desired, welding repairs of such forgings may
be made, inspected, and tested at the shop of the pressure
vessel manufacturer.
ATTACHMENT OF THREADED
NOZZLES TO INTEGRALLY
FORGED NECKS AND THICKENED
HEADS ON VESSELS
Threaded openings, over NPS 3 (DN 80), but not
exceeding the smaller of one-half of the vessel diameter
or NPS 8, may be used in the heads of vessels having
integrally forged heads and necks that are so shaped and
thickened as to provide a center opening, which shall meet
the rules governing openings and reinforcements contained
elsewhere in the Code. Length of thread shall be calculated
for the opening design, but shall not be less than shown
in Table UG-43. Threaded connections employing straight
threads shall provide for mechanical seating of the assembly by a shoulder or similar means. When seal welding is
employed in the installation of a threaded nozzle, the work
shall be performed and inspected in the shop of the vessel
manufacturer. Seal welding shall comply with UF-32.
UF-52
INSPECTION AND TESTS
UF-45
ACCEPTANCE BY INSPECTOR
CHECK OF HEAT TREATMENT AND
POSTWELD HEAT TREATMENT
The Inspector shall check the provisions made for heat
treatment to assure himself that the heat treatment is carried
out in accordance with provisions of UF-31 and UF-32.
He shall also assure himself that postweld heat treatment
is done after repair welding when required under the rules
of UF-37.
GENERAL
The rules in the following paragraphs apply specifically
to the inspection and testing of forged vessels and their
component parts. These rules shall be used to supplement
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2010 SECTION VIII — DIVISION 1
UF-53
TEST SPECIMENS
exceeding in amplitude the indication from the calibrated
notch. Round bottom surface imperfections, such as pits,
scores, and conditioned areas, producing indications
exceeding the amplitude of the calibrated notch shall be
acceptable if the thickness below the indication is not less
than the design wall thickness of the vessel, and its sides
are faired to a ratio of not less than three to one.
When test specimens are to be taken under the applicable
specification, the Inspector shall be allowed to witness
the selection, place the identifying stamping on them, and
witness the testing of these specimens.
UF-54
TESTS AND RETESTS
Tests and retests shall be made in accordance with the
requirements of the material specification.
MARKING AND REPORTS
UF-115
UF-55
GENERAL
The rules of UG-115 through UG-120 shall apply to
forged vessels as far as practicable. Vessels constructed of
liquid quenched and tempered material, other than austenitic steels, shall be marked on the thickened head, unless
a nameplate is used.
ULTRASONIC EXAMINATION
(a) For vessels constructed of SA-372 Grade J, Class
110 material, the completed vessel after heat treatment
shall be examined ultrasonically in accordance with
SA-388. The reference specimen shall have the same nominal thickness, composition, and heat treatment as the vessel
it represents. Angle beam examination shall be calibrated
with a notch of a depth equal to 5% of the nominal section
thickness, a length of approximately 1 in. (25 mm), and a
width not greater than twice its depth.
(b) A vessel is unacceptable if examination results show
one or more imperfections which produce indications
PRESSURE RELIEF DEVICES
UF-125
GENERAL
The provisions for pressure relief devices of UG-125
through UG-136 shall apply without supplement.
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2010 SECTION VIII — DIVISION 1
PART UB
REQUIREMENTS FOR PRESSURE VESSELS
FABRICATED BY BRAZING
specifications in Section II and shall be limited to those
materials for which allowable stress values have been
assigned in the tables referenced by UG-23.
(b) Combinations of dissimilar metals may be joined
by brazing provided they meet the qualification requirements of Section IX, and the additional requirements of
UB-12 when applicable.
GENERAL
UB-1
SCOPE
(a) The rules in Part UB are applicable to pressure vessels and parts thereof that are fabricated by brazing and
shall be used in conjunction with the general requirements
in Subsection A, and with the specific requirements in
Subsection C that pertain to the class of material used.
(b) Definition. The term brazing as used in Part UB
is defined as a group of welding processes that produce
coalescence of materials by heating them to the brazing
temperature in the presence of a filler metal having liquidus
above 840°F (450°C) and below the solidus of the base
metal. The filler metal is distributed between the closely
fitted surfaces of the joint by capillary attraction.
(c) Specific brazing processes which are permitted for
use under this Division are classified by method of heating
as follows:
(1) torch brazing;
(2) furnace brazing;
(3) induction brazing;
(4) electrical resistance brazing;
(5) dip brazing — salt and flux bath.
UB-2
UB-6
The selection of the brazing filler metal for a specific
application shall depend upon its suitability for the base
metals being joined and the intended service. Satisfactory
qualification of the brazing procedure under Section IX
and when necessary based on design temperature, with the
additional requirements of this Section, is considered proof
of the suitability of the filler metal. Brazing with brazing
filler metals other than those listed in Section II, Part C,
SFA-5.8 shall be separately qualified for both procedure
and performance qualification in accordance with Section
IX and when necessary with the additional requirements
of this Section.
ELEVATED TEMPERATURE
UB-7
Operating temperature is dependent on the brazing filler
metal as well as on the base metals being joined. The
maximum allowable operating temperatures for the brazing
filler metals are shown in Table UB-2.
UB-3
FLUXES AND ATMOSPHERES
Suitable fluxes or atmospheres or combinations of fluxes
and atmospheres shall be used to prevent oxidation of the
brazing filler metal and the surfaces to be joined. Satisfactory qualification of the brazing procedure under Section
IX and when necessary based on design temperature, with
the additional requirements of this Section, is considered
proof of the suitability of the flux and/or atmosphere.
SERVICE RESTRICTIONS
Brazed vessels shall not be used for services as follows:
(a) lethal services as defined in UW-2(a);
(b) unfired steam boilers as defined in U-1(g);
(c) direct firing [see UW-2(d)].
DESIGN
UB-9
MATERIALS
UB-5
BRAZING FILLER METALS
GENERAL
The rules in the following paragraphs apply specifically
to pressure vessels and parts thereof that are fabricated by
brazing and shall be used in conjunction with the general
requirements for Design in Subsection A, and the specific
GENERAL
(a) Materials used in the construction of pressure vessels and parts thereof by brazing shall conform to the
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2010 SECTION VIII — DIVISION 1
TABLE UB-2
MAXIMUM DESIGN TEMPERATURES FOR BRAZING FILLER METAL
Filler Metal
Classification
Column 1
Temperature, °F (°C),
Below Which Section IX
Tests Only Are Required
(150)
(200)
(200)
(200)
Column 2
Temperature, °F (°C), Range
Requiring Section IX and
Additional Tests
BCuP
BAg
BCuZn
BCu
300
400
400
400
300–350
400–500
400–500
400–650
(150–180)
(200–260)
(200–260)
(200–340)
BAlSi
300 (150)
300–350 (150–180)
BNi
BAu
BMg
1200 (650)
800 (430)
250 (120)
1200–1500 (650–815)
800–900 (430–480)
250–275 (120–135)
GENERAL NOTE: Temperatures based on AWS recommendations.
requirements for Design in Subsection C that pertain to
the class of material used.
UB-10
tension tests on production type joints are required, one at
the design temperature, T, and one at 1.05T. Neither of
these production type joints shall fail in the braze metal.
STRENGTH OF BRAZED JOINTS
UB-13
It is the responsibility of the Manufacturer to determine
from suitable tests or from experience that the specific
brazing filler metal selected can produce a joint which will
have adequate strength at design temperature. The strength
of the brazed joint shall not be less than the strength of
the base metal, or the weaker of two base metals in the
case of dissimilar metal joints.
UB-11
(a) Provision shall be made for corrosion in accordance
with the requirements in UG-25.
(b) Corrosion of the brazing filler metal and galvanic
action between the brazing filler metal and the base metals
shall be considered in selecting the brazing filler metal.
(c) The plate thickness in excess of that computed for
a seamless vessel taking into account the applicable loadings in UG-22 may be taken as allowance for corrosion in
vessels that have longitudinal joints of double-strap butt
joint construction. Additional corrosion allowance shall be
provided when needed, particularly on the inner buttstraps.
(d) The rules in this Part are not intended to apply to
brazing used for the attachment of linings of corrosion
resistant material that are not counted on to carry load.
QUALIFICATION OF BRAZED
JOINTS FOR DESIGN
TEMPERATURES UP TO THE
MAXIMUM SHOWN IN COLUMN 1
OF TABLE UB-2
Satisfactory qualification of the brazing procedure in
accordance with Part QB of Section IX is considered evidence of the adequacy of the base materials, the brazing
filler metal, the flux and/or atmosphere, and other variables
of the procedure.
UB-12
CORROSION
UB-14
JOINT EFFICIENCY FACTORS
(a) The joint efficiency factor to be used in the appropriate design equations of pressure vessels and parts thereof
shall be 1.0 for joints in which visual examination assures
that the brazing filler metal has penetrated the entire joint
[see Fig. UB-14 sketch (a)].
(b) The joint efficiency factor to be used in the appropriate design equations of pressure vessels and parts thereof
shall be 0.5 for joints in which visual examination will not
provide proof that the brazing filler metal has penetrated
the entire joint. [See Fig. UB-14 sketch (b); UB-15(b)
and (c).]
(c) The appropriate joint efficiency factor to be used in
design equations for seamless flat heads and seamless
QUALIFICATION OF BRAZED
JOINTS FOR DESIGN
TEMPERATURES IN THE RANGE
SHOWN IN COLUMN 2 OF TABLE
UB-2
For design temperatures in the range shown in Column
2 of Table UB-2, tests in addition to those in UB-11 are
required. These tests shall be considered a part of the
qualification procedure. For such design temperatures, two
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2010 SECTION VIII — DIVISION 1
FIG. UB-14 EXAMPLES OF FILLER METAL APPLICATION
Brazing filler
metal ring
preplaced here
Brazing filler
metal preplaced
in form of:
(a) powder plus
binder
(b) ring
(c) clad sheet
(d) shim stock
c
a
Brazing filler metal
preplaced or manually
applied here
b
Brazing filler metal
manually applied
here
d
GENERAL NOTE:
A 0.5 factor may be
used in design.
GENERAL NOTE:
A 1.0 factor may be
used in design.
(b)
(a)
formed heads, excluding seamless hemispherical heads, is
1.0. The appropriate joint efficiency factor to be used in
design equations for circumferential stress in seamless
cylindrical or conical shells is 1.0.
UB-15
joint in such a manner that it penetrates the major portion
of the joint during brazing and appears at the visible side
of the joint, a joint efficiency factor of 1.0 may be used
in the design of the joint. If the brazing filler metal is
preplaced on the outside or near the outside of a blind
joint, and the other side cannot be inspected to ascertain
complete penetration, then a joint efficiency factor of 0.5
shall be used in the design of the joint as provided in
UB-14(b). Figure UB-14 illustrates a few examples of
this rule.
APPLICATION OF BRAZING FILLER
METAL
(a) The design shall provide for the application of the
brazing filler metal as part of the design of the joint. Where
practicable, the brazing filler metal shall be applied in such
a manner that it will flow into the joint or be distributed
across the joint and produce visible evidence that it has
penetrated the joint.
(b) Manual Application. The manual application of the
brazing filler metal by face feeding to a joint should be
from the one side only. Visual observation of the other
side of the joint will then show if the required penetration
of the joint by the filler metal has been obtained. If the side
opposite to the filler metal application cannot be visually
examined, as is the case with socket type joints in pipe
and tubing (blind joint), a joint efficiency factor of 0.5
shall be used in design of this joint as provided in UB-14(b).
(c) Preplaced Brazing Filler Metal. The brazing filler
metal may be preplaced in the form of slugs, powder, rings,
strip, cladding, spraying or other means. After brazing, the
brazing filler metal should be visible on both sides of the
joint. If the brazing filler metal is preplaced within a blind
UB-16
PERMISSIBLE TYPES OF JOINTS
(a) Some permissible types of brazed joints are shown
in Fig. UB-16. For any type of joint, the strength of the
brazed section shall exceed that of the base metal portion
of the test specimen in the qualification tension tests provided for in QB-150 of Section IX. Lap joints shall have
a sufficient overlap to provide a higher strength in the
brazed joint than in the base metal.
(b) The nominal thickness of base material used with
lap joints tested using the test fixture shown in QB-462.1(e)
shall not exceed 1⁄2 in. (13 mm). There is no thickness
limitation when specimens are tested without the test fixture shown in QB-462.1(e).
UB-17
JOINT CLEARANCE
The joint clearance shall be kept sufficiently small so
that the filler metal will be distributed by capillary
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2010 SECTION VIII — DIVISION 1
FIG. UB-16 SOME ACCEPTABLE TYPES OF BRAZED JOINTS
GENERAL NOTE: Other equivalent geometries yielding substantially equal results are also acceptable.
TABLE UB-17
RECOMMENDED JOINT CLEARANCES AT BRAZING
TEMPERATURE
Brazing Filler Metal
Clearance, in. (mm) [Note (1)]
BAlSi
0.006–0.010 (0.15–0.25) for laps less
than or equal to 1⁄4 in. (6 mm)
0.010–0.025 (0.25–0.64) for laps
greater than 1⁄4 in. (6 mm)
0.001–0.005 (0.02–0.13)
0.002–0.005 (0.05–0.13)
0.002–0.005 (0.05–0.13)
0.000–0.002 (0.05–0.13) [Note (2)]
0.001–0.005 (0.02–0.13)
BCuP
BAg
BCuZn
BCu
BNi
in QB-482 of Section IX. If more than one joint occurs in
a brazed assembly, the brazing sequence shall be specified
on the drawing or in instructions accompanying the drawing. If welding and brazing are to be done on the same
assembly, the welding shall precede the brazing unless it
is determined that the heat of welding will not adversely
affect the braze previously made.
UB-19
(a) Openings for nozzles and other connections shall
be far enough away from any main brazed joint so that
the joint and the opening reinforcement plates do not interfere with one another.
(b) Openings for pipe connections in vessels having
brazed joints may be made by inserting pipe couplings,
not exceeding NPS 3 (DN 80), or similar devices in the
shell or heads and securing them by welding, without
necessitating the application of the restrictive stamping
provisions of UG-116, provided the welding is performed
by welders who have been qualified under the provisions
of Section IX for the welding position and type of joint
used. Such attachments shall conform to the rules for
welded connections in UW-15 and UW-16.
NOTES:
(1) In the case of round or tubular members, clearance on the radius
is intended.
(2) For maximum strength, use the smallest possible clearance.
attraction. Since the strength of a brazed joint tends to
decrease as the joint clearance used is increased, the clearances for the assembly of joints in pressure vessels or parts
thereof shall be within the tolerances set up by the joint
design and as used for the corresponding qualification specimens made in accordance with Section IX and UB-12
where applicable.
NOTE: For guidance, see Table UB-17 which gives recommended joint
clearances at brazing temperature for various types of brazing filler metal.
Brazing alloys will exhibit maximum unit strength if clearances are maintained within these limits.
UB-18
OPENINGS
UB-20
NOZZLES
(a) Nozzles may be integral or attached to the vessel
by any of the methods provided for in UG-43.
(b) For nozzle fittings having a bolting flange and an
integral flange for brazing, the thickness of the flange
attached to the pressure vessel shall not be less than the
thickness of the neck of the fitting.
JOINT BRAZING PROCEDURE
A joint brazing procedure shall be developed for each
different type of joint of a brazed assembly. A recommended form for recording the brazing procedure is shown
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2010 SECTION VIII — DIVISION 1
UB-21
BRAZED CONNECTIONS
(4) The Manufacturer’s Quality Control System shall
include as a minimum:
(a) a requirement for complete and exclusive
administrative and technical supervision of all brazers by
the Manufacturer;
(b) evidence of the Manufacturer’s authority to
assign and remove brazers at his discretion without the
involvement of any other organization;
(c) a requirement for assignment of brazer identification symbols;
(d) evidence that this program has been accepted
by the Manufacturer’s Authorized Inspection Agency
which provides the inspection service.
(5) The Manufacturer shall be responsible for Code
compliance of the vessel or part, including Code Symbol
stamping and providing completed Data Report Forms.
Connections, such as saddle type fittings and fittings
inserted into openings formed by outward flanging of the
vessel wall, in sizes not exceeding NPS 3 (DN 80), may
be attached to pressure vessels by lap joints of brazed
construction. Sufficient brazing shall be provided on either
side of the line through the center of the opening parallel
to the longitudinal axis of the shell to develop the strength
of the reinforcement as prescribed in UG-41 through shear
in the brazing.
UB-22
LOW TEMPERATURE OPERATION
Impact tests shall be made of the brazed joints in pressure
vessels and parts thereof fabricated from materials for
which impact tests are required in Subsection C. The tests
shall be made in accordance with UG-84 except that terms
referring to welding shall be interpreted as referring to
brazing.
UB-31
(a) Each procedure of brazing that is to be followed in
construction shall be recorded in detail by the Manufacturer. Each brazing procedure shall be qualified in accordance with Section IX and when necessary determined by
design temperature, with the additional requirements of
this Section.
(b) The procedure used in brazing pressure parts and in
joining load-carrying nonpressure parts, such as all permanent or temporary clips and lugs, to pressure parts shall
be qualified in accordance with Section IX.
(c) The procedure used in brazing nonpressure-bearing
attachments which have essentially no load-carrying function (such as extended heat transfer surfaces, insulation
support pins, etc.) to pressure parts shall meet the following
requirements:
(1) When the brazing process is manual, machine,
or semiautomatic, procedure qualification is required in
accordance with Section IX.
(2) When the brazing is any automatic brazing process performed in accordance with a Brazing Procedure
Specification (in compliance with Section IX as far as
applicable), procedure qualification testing is not required.
(d) Brazing of all test coupons shall be conducted by
the Manufacturer. Testing of all test coupons shall be the
responsibility of the Manufacturer. Qualification of a brazing procedure by one Manufacturer shall not qualify that
procedure for any other Manufacturer, except as provided
in QW-201 of Section IX.
FABRICATION
UB-30
QUALIFICATION OF BRAZING
PROCEDURE
GENERAL
(a) The rules in the following paragraphs apply specifically to the fabrication of pressure vessels and parts thereof
that are fabricated by brazing and shall be used in conjunction with the requirements for Fabrication in Subsection
A, and with the specific requirements for Fabrication in
Subsection C that pertain to the class of material used.
(b) Each manufacturer or contractor shall be responsible
for the quality of the brazing done by his organization and
shall conduct tests not only of the brazing procedure to
determine its suitability to ensure brazes which will meet
the required tests, but also of the brazers and brazing operators to determine their ability to apply the procedure
properly.
(c) No production work shall be undertaken until both
the brazing procedure and the brazers or brazing operators
have been qualified.
(d) Brazers not in the employ of the Manufacturer (Certificate of Authorization Holder) may be used to fabricate
pressure vessels constructed in accordance with this Division, provided all the following conditions are met:
(1) All Code construction shall be the responsibility
of the Manufacturer.
(2) All brazing shall be performed in accordance with
the Manufacturer’s Brazing Procedure Specifications
which have been qualified by the Manufacturer in accordance with the requirements of Section IX.
(3) All brazers shall be qualified by the Manufacturer
in accordance with the requirements of Section IX.
UB-32
QUALIFICATION OF BRAZERS AND
BRAZING OPERATORS
(a) The brazers and brazing operators used in brazing
pressure parts and in joining load-carrying nonpressure
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2010 SECTION VIII — DIVISION 1
parts (attachments) to pressure parts shall be qualified in
accordance with Section IX.
(1) The qualification test for brazing operators of
machine brazing equipment shall be performed on a separate test plate prior to the start of brazing or on the first
workpiece.
(b) The brazers and brazing operators used in brazing
nonpressure-bearing attachments, which have essentially
no load-carrying function (such as extended heat transfer
surfaces, insulation support pins, etc.), to pressure parts
shall comply with the following:
(1) When the brazing process is manual, machine, or
semiautomatic, qualification in accordance with Section
IX is required.
(2) When brazing is done by any automatic brazing
process, performance qualification testing is not required.
(c) Each brazer or brazing operator shall be assigned an
identifying number, letter, or symbol by the Manufacturer
which shall be used to identify the work of that brazer or
brazing operator in accordance with UW-37(f).
(d) The Manufacturer shall maintain a record of the
brazers and brazing operators showing the date and result
of tests and the identification mark assigned to each. These
records shall be maintained in accordance with Section IX.
(e) Brazing of all test coupons shall be conducted by
the Manufacturer. Testing of all test coupons shall be the
responsibility of the Manufacturer. A performance qualification test conducted by one Manufacturer shall not qualify
a brazer or brazing operator to do work for any other
Manufacturer.
UB-33
UB-35
The clearances between surfaces to be brazed shall be
maintained within the tolerances provided for by the joint
design and used in the qualifying procedure. If greater
tolerances are to be used in production, the joint must
be requalified for those greater tolerances. The control of
tolerances required may be obtained by using spot welding,
crimping, or other means which will not interfere with
the quality of the braze. If such means are employed in
production, they must also be employed in qualification of
procedure, brazer, and operator.
UB-36
POSTBRAZING OPERATIONS
Brazed joints shall be thoroughly cleaned of flux residue
by any suitable means after brazing and prior to inspection.1
Other postbrazing operations such as thermal treatments
shall be performed in accordance with the qualified procedure.
UB-37
REPAIR OF DEFECTIVE BRAZING
Brazed joints which have been found to be defective
may be rebrazed, where feasible, after thorough cleaning,
and by employing the same brazing procedure used for the
original braze. See UB-44. If a different brazing procedure
is employed, i.e., torch repair of furnace brazed parts, a
repair brazing procedure shall be established and qualified.
When a repair brazing procedure is established, it shall
meet Section IX and other conditions set forth in this
Section.
BUTTSTRAPS
(a) Buttstraps shall be formed to the curvature of the
shell with which they are to be used.
(b) When the buttstraps of a longitudinal joint do not
extend the full length of a shell section, the abutting edges
of the shell plate may be welded provided the length of
the weld between the end of the buttstraps and the edge
of the head or adjoining shell plate is not greater than four
times the shell plate thickness. When so constructed, the
restrictive stamping provisions of UG-116 shall not apply
provided the welding is performed by welders who have
been qualified under the provisions of Section IX for the
welding position and type of joint used. The welds shall
be completed before brazing is begun.
INSPECTION AND TESTS
UB-40
GENERAL
The rules in the following paragraphs apply specifically
to the inspection and testing of pressure vessels and parts
thereof that are fabricated by brazing and shall be used in
conjunction with the general requirements for Inspection
and Tests in Subsection A and with the specific requirements for Inspection and Tests in Subsection C that pertain
to the class of material used.
UB-41
UB-34
CLEARANCE BETWEEN SURFACES
TO BE BRAZED
CLEANING OF SURFACES TO BE
BRAZED
INSPECTION DURING
FABRICATION
The Manufacturer shall submit the vessel or other pressure parts for inspection at such stages of the work as may
be designated by the Inspector.
The surfaces to be brazed shall be clean and free from
grease, paint, oxides, scale and foreign matter of any kind.
Any chemical or mechanical cleaning method may be used
that will provide a surface suitable for brazing.
1
Flux residues can be extremely corrosive as well as interfering with
visual inspection.
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2010 SECTION VIII — DIVISION 1
UB-42
PROCEDURE
be used if desired. The braze may be repaired or rebrazed.
See UB-37.
(d) The presence of a crack in the base metal adjacent
to a braze shall be cause for rejection even if the crack
is filled with brazing alloy. Such cracking shall not be
repaired.
(e) Pinholes or open defects in the braze shall be cause
for rejection. The joint may be rebrazed.
(f) Rough fillets, particularly those with a convex
appearance, are cause for rejection. Such joints may be
repaired or rebrazed.
The Inspector shall assure himself that the brazing procedure for each type of joint being produced is qualified in
accordance with the requirements of Section IX and when
necessary the additional requirements of this Section. He
shall satisfy himself that each joint has been fabricated in
accordance with the procedure. Where there is evidence
of consistent poor quality, the Inspector shall have the right
at any time to call for and witness tests of the brazing
procedure.
UB-43
BRAZER AND BRAZING OPERATOR
(a) The manufacturer shall certify that the brazing on
a vessel or part thereof has been done by brazers or brazing
operators who are qualified under the requirements of Section IX and the Inspector shall assure himself that only
qualified brazers or brazing operators have been used.
(b) The manufacturer shall make available to the Inspector the record of the qualification tests of each brazer and
brazing operator. The Inspector shall have the right at any
time to call for and witness tests of the ability of a brazer
or brazing operator.
UB-50
EXEMPTIONS
Certain brazed joints regardless of their service temperatures may be exempt from the additional mechanical testing
of this Section providing that the design application does
not assume any benefit from the brazed joint strength. It
shall, however, meet the requirements of those qualification
tests required by Section IX of the Code.
MARKING AND REPORTS
UB-44
VISUAL EXAMINATION
UB-55
(a) Where possible, the Inspector shall visually inspect
both sides of each brazed joint after flux residue removal.
Where it is not possible to inspect one side of a brazed
joint (blind joint), the Inspector shall check the design to
determine that the proper joint factor has been employed,
unless he can assure himself that the brazing filler metal
has been preplaced in such a manner that it satisfies
UB-15(b) and (c).
(b) There shall be evidence that the brazing filler metal
has penetrated the joint. In a butt braze there shall be no
concavity. The braze may be repaired or rebrazed.
(c) The presence of a crack in the brazing filler metal
shall be cause for rejection. Dye penetrant inspection may
GENERAL
The provisions for marking and reports given in UG-115
through UG-120 shall apply without supplement to brazed
pressure vessels and parts thereof.
PRESSURE RELIEF DEVICES
UB-60
GENERAL
The provisions for pressure relieving devices given in
UG-125 through UG-136 shall apply without supplement
to brazed pressure vessels.
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2010 SECTION VIII — DIVISION 1
SUBSECTION C
REQUIREMENTS PERTAINING
TO CLASSES OF MATERIALS
PART UCS
REQUIREMENTS FOR PRESSURE VESSELS
CONSTRUCTED OF CARBON AND
LOW ALLOY STEELS1
exceed those of the material specification for the pressure
part to which it is attached.
(2) Either of the following requirements shall be met:
(a) The backing strip base metal, and its associated
HAZ, and the weld metal shall be impact tested in accordance with UG-84 at the MDMT shown on the nameplate
with a butt weld test specimen to the pressure part material
or to a material with the same P-No. and Group No. as
the pressure part.
(b) The material is assigned to Curve A and is
exempt from impact testing at the MDMT shown on the
nameplate by Fig. UCS-66 alone (i.e., MDMT reduction
per Fig. UCS-66.1 is not permitted), and both of the following apply:
(1) The backing strip material specification minimum tensile strength shall not exceed that of the pressure
part material specification.
(2) The backing strip material specification minimum percent elongation shall be at least equal to that for
the pressure part material specification.
(c) Carbon or low alloy steel having a carbon content
of more than 0.35% by heat analysis shall not be used in
welded construction or be shaped by oxygen cutting
(except as provided elsewhere in this Division).
(d) Small parts used under the provisions of
UG-11(a)(2) in welded construction shall be of good weldable quality.
GENERAL
UCS-1
SCOPE
The rules in Part UCS are applicable to pressure vessels
and vessel parts that are constructed of carbon and low alloy
steels and shall be used in conjunction with the general
requirements in Subsection A, and with the specific requirements in Subsection B that pertain to the method of fabrication used.
MATERIALS
UCS-5
GENERAL
(a) All carbon and low alloy steel material subject to
stress due to pressure shall conform to one of the Specifications given in Section II and shall be limited to those listed
in Table UCS-23 except as otherwise provided in UG-10
and UG-11.
(b) In addition to the requirements of UG-4(a), backing
strips which remain in place need not conform to a material
specification permitted by this Division if all of the following are met:
(1) The specification maximum composition limits
or certificate values for the backing strip material shall not
1
Low alloy steels — those alloy steels listed in Table UCS-23.
164
2010 SECTION VIII — DIVISION 1
UCS-6
STEEL PLATES
(b) Nonferrous and high alloy steel bolts, studs, and
nuts may be used provided they are suitable for the application. They shall conform to the requirements of Part UNF
or UHA, as applicable.
(a) Approved specifications for carbon and low alloy
steel plates are given in Table UCS-23. A tabulation of
allowable stress values at different temperatures are given
in Table 1A of Section II, Part D (see UG-5).
(b) Steel plates conforming to SA-36, SA/CSA-G40.21
38W, and SA-283 Grades A, B, C, and D may be used
for pressure parts in pressure vessels provided all of the
following requirements are met:
(1) The vessels are not used to contain lethal substances, either liquid or gaseous.
(2) The material is not used in the construction of
unfired steam boilers [see U-1(g)].
(3) With the exception of flanges, flat bolted covers,
and stiffening rings, the thickness of plates on which
strength welding is applied does not exceed 5⁄8 in. (16 mm).
UCS-7
UCS-11
(a) Except as otherwise provided in (b)(4) below, materials for nuts shall conform to SA-194, SA-563, or to the
requirements for nuts in the specification for the bolting
material with which they are to be used. Nuts of special
design, such as wing nuts, may be made of any suitable
wrought material listed in Table UCS-23 or Table UHA23 and shall be either: hot or cold forged; or machined
from hot-forged, hot-rolled, or cold-drawn bars. Washers
may be made from any suitable material listed in Table
UCS-23 and Table UHA-23.
(b) Materials for nuts and washers shall be selected as
follows:
(1) Carbon steel nuts and carbon steel washers may
be used with carbon steel bolts or studs.
(2) Carbon or alloy steel nuts and carbon or alloy
steel washers of approximately the same hardness as the
nuts may be used with alloy steel bolts or studs for metal
temperatures not exceeding 900°F (480°C).
(3) Alloy steel nuts shall be used with alloy steel studs
or bolts for metal temperatures exceeding 900°F (480°C).
Washers, if used, shall be of alloy steel equivalent to the
nut material.
(4) Nonferrous nuts and washers may be used with
ferrous bolts and studs provided they are suitable for the
application. Consideration shall be given to the differences
in thermal expansion and possible corrosion resulting from
the combination of dissimilar metals. Nonferrous nuts and
washers shall conform to the requirements of UNF-13.
(c) Nuts shall be semifinished, chamfered, and trimmed.
Nuts shall be threaded to Class 2B or finer tolerances
according to ASME B1.1. For use with flanges conforming
to the standards listed in UG-44, nuts shall conform at
least to the dimensions given in ASME B18.2.2 for Heavy
Series nuts. For use with connections designed in accordance with the rules in Appendix 2, nuts may be of the
ANSI Heavy Series, or they may be of other dimensions
as permitted in (d) below.
(d) Nuts of special design or of dimensions other than
ANSI Heavy Series may be used provided their strength
is equal to that of the bolting, giving due consideration to
bolt hole clearance, bearing area, thread form and class of
fit, thread shear, and radial thrust from threads [see U-2(g)].
STEEL FORGINGS
Approved specifications for forgings of carbon and low
alloy steel are given in Table UCS-23. A tabulation of
allowable stress values at different temperatures are given
in Table 1A of Section II, Part D (see UG-6).
UCS-8
STEEL CASTINGS
Approved specifications for castings of carbon and low
alloy steel are given in Table UCS-23. A tabulation of
allowable stress values at different temperatures are given
in Table 1A of Section II, Part D. These stress values are
to be multiplied by the casting quality factors of UG-24.
Castings that are to be welded shall be of weldable grade.
UCS-9
STEEL PIPE AND TUBES
Approved specifications for pipe and tubes of carbon
and low alloy steel are given in Table UCS-23. A tabulation
of allowable stress values of the materials from which the
pipe or tubes are manufactured are given in Table 1A of
Section II, Part D. Net allowable stress values for pipe or
tubes of welded manufacture are given in Table 1A of
Section II, Part D.
UCS-10
NUTS AND WASHERS
BOLT MATERIALS
(a) Approved specifications for bolt materials of carbon
steel and low alloy steel are given in Table UCS-23. A
tabulation of allowable stress values at different temperatures (see UG-12) are given in Table 3 of Section II, Part D.
UCS-12
BARS AND SHAPES
(a) Approved specifications for bar and shape materials
of carbon steel are given in Table UCS-23. A tabulation
165
2010 SECTION VIII — DIVISION 1
TABLE UCS-23
CARBON AND LOW ALLOY STEEL
(10)
Spec.
No.
Type/Grade
Spec.
No.
Type/Grade
Spec. No.
Type/Grade
SA-36
...
SA-302
A, B, C, D
SA-516
55, 60, 65, 70
SA-53
E/A, E/B, S/A, S/B
SA-307
B
SA-524
I, II
SA-105
SA-106
...
A, B, C
SA-320
L7, L7A, L7M, L43
SA-533
SA-325
1
SA-135
A, B
SA-537
SA-540
A Cl. 1 & 2, B Cl. 1 & 2, C
Cl. 1 & 2, D Cl. 2
Cl. 1, 2 & 3
B21, B22, B23, B24, B24V
SA-178
SA-179
A, C
...
SA-333
SA-334
SA-335
SA-181
SA-182
...
FR, F1, F2, F3V, F3VCb,
F5, F5a, F9, F11 Cl.
1 & 2, F12 Cl. 1 & 2,
F21, F22 Cl. 1 & 3,
F22V, F91
1, 3, 4, 6, 7, 9
1, 3, 6, 7, 9
P1, P2, P5, P5b, P5c, P9,
P11, P12, P15, P21,
P22, P91
F1, F3V, F3VCb, F5, F5A,
F9, F11 Cl. 2 & 3, F12,
F21 Cl. 1 & 3, F22 Cl.
1 & 3, F22V, F91
SA-556
SA-557
A2, B2, C2
A2, B2, C2
SA-350
LF1, LF2, LF3, LF5, LF9
SA-562
...
SA-352
SA-354
LCB, LC1, LC2, LC3
BC, BD
SA-574
4037, 4042, 4140, 4340,
5137M, 51B37M
SA-369
FP1, FP2, FP5, FP9,
FP11, FP12, FP21,
FP22
SA-587
...
SA-612
...
A, B, C, D, E Cl.65 & 70, F
Cl. 70, G Cl. 70, H Cl.
70, J Cl. 65, 70 & 110,
L, M Cl. A & B
SA-662
A, B, C
SA-675
45, 50, 55, 60, 65, 70
SA-695
B/35, B/40
SA-727
...
SA-737
SA-738
SA-739
B, C
A, B, C
B11, B22
SA-765
I, II, III, IV
SA-192
SA-193
...
B5, B7, B7M, B16
SA-202
SA-203
SA-204
SA-209
SA-210
A, B
A, B, D, E, F
A, B, C
T1, T1a, T1b
A-1, C
SA-213
T2, T5, T5b, T5c, T9,
T11, T12, T17, T21,
T22, T91
...
WCA, WCB, WCC
C12, C5, WC1, WC4,
WC5, WC6, WC9
SA-336
SA-372
SA-214
SA-216
SA-217
SA-387
2, 5, 11, 12, 21, 22, 91
SA-414
A, B, C, D, E, F, G
SA-541
SA-542
1, 1A, 2 Cl. 1, 2 Cl. 2, 3
Cl. 1, 3 Cl. 2, 3V, 3VCb,
22 Cl. 3, 22V
B Cl. 4, C Cl. 4a, D Cl. 4a,
E Cl. 4a
SA-225
C
SA-420
WPL 3, WPL 6, WPL 9
SA-234
WPB, WPC, WPR, WP1,
WP5, WP9, WP11 Cl.
1, WP12 Cl. 1, WP22
Cl. 1
SA-423
1, 2
SA-437
B4B, B4C
SA-449
...
SA-832
21V, 22V, 23V
SA-455
...
SA-836
...
SA-487
1 Cl. A & B, 2 Cl. A & B, 4
Cl. A, 8 Cl. A
SA-1008
CS-A, CS-B
SA/AS 1548
7-430, 7-460, 7-490
SA-508
1, 1A, 2 Cl. 1, 2 Cl. 2, 3
Cl. 1, 3 Cl. 2, 3V, 3VCb,
4N Cl. 3, 22 Cl. 3
SA/CSA-G40.21
38W
60, 65, 70
SA/EN 10028-2
SA/EN 10028-3
SA/GB 6654
P295GH, P355GH
P275NH
16 MnR
SA-250
T1, T1a, T1b
SA-266
1, 2, 3, 4
SA-283
SA-285
A, B, C, D
A, B, C
SA-299
...
SA-515
GENERAL NOTE: Maximum allowable stress values in tension for the materials listed in the above table are contained in Subpart 1 of Section
II, Part D (see UG-23).
166
2010 SECTION VIII — DIVISION 1
of allowable stress values at different temperatures are
given in Table 1A of Section II, Part D.
(b) Bolt materials as described in UCS-10 may be used
as bar materials.
(c) Parts made from bars, on which welding is done,
shall be of material for which a P-Number for procedure
qualification is given in Section IX, QW-422 (see UW-5).
mm) provided the material is manufactured by the openhearth, basic oxygen, or electric-furnace process [see
UG-16(d)].
UCS-28
(a) Cylindrical and spherical shells under external pressure shall be designed by the rules in UG-28, using the
applicable figures in Subpart 3 of Section II, Part D and
the temperature limits of UG-20(c).
(b) Examples illustrating the use of the charts in the
figures for the design of vessels under external pressure
are given in Appendix L.
(c) Corrugated shells subject to external pressure may
be used in pressure vessels in accordance with PFT-19 of
Section I.
DESIGN
UCS-16
GENERAL
The rules in the following paragraphs apply specifically
to the design of pressure vessels and vessel parts that are
constructed of carbon and low alloy steel and shall be used
in conjunction with the general requirements for Design
in Subsection A and with the specific requirements for
Design in Subsection B that pertain to the method of fabrication used.
UCS-19
UCS-29
UCS-30
ATTACHMENT OF STIFFENING
RINGS TO SHELL
Rules covering the attachment of stiffening rings are
given in UG-30.
MAXIMUM ALLOWABLE STRESS
VALUES
Tables 3 (for bolting) and 1A (other materials) in Section
II, Part D give the maximum allowable stress values at
the temperature indicated for materials conforming to the
specifications listed therein.2 Values may be interpolated
for intermediate temperatures. (See UG-23.) For vessels
designed to operate at a temperature below −20°F (−29°C),
the allowable stress values to be used in design shall not
exceed those given in Table 3 or 1A in Section II, Part D
for 100°F (40°C).
UCS-27
STIFFENING RINGS FOR SHELLS
UNDER EXTERNAL PRESSURE
Rules covering the design of stiffening rings are given
in UG-29. An example illustrating the use of these rules
is given in Appendix L.
WELDED JOINTS
When radiographic examination is required for butt
welded joints by UCS-57, joints of Categories A and B
(see UW-3) shall be of Type No. (1) or No. (2) of Table
UW-12.
UCS-23
THICKNESS OF SHELLS UNDER
EXTERNAL PRESSURE
UCS-33
FORMED HEADS, PRESSURE ON
CONVEX SIDE
Ellipsoidal, torispherical, hemispherical, and conical
heads having pressure on the convex side (minus heads)
shall be designed by the rules of UG-33, using Fig. CS-1
or Fig. CS-2 of Subpart 3 of Section II, Part D. Examples
illustrating the application of this paragraph are given in
Appendix L.
SHELLS MADE FROM PIPE
UCS-56
(a) Shells of pressure vessels may be made from seamless pipe or tubing listed in Table 1A of Section II, Part
D provided the material of the pipe is manufactured by
the open-hearth, basic oxygen, or electric-furnace process.
(b) Shells of pressure vessels may be made from electric
resistance welded pipe or tubing listed in Table 1A of
Section II, Part D in nominal diameters up to 30 in. (750
REQUIREMENTS FOR POSTWELD
HEAT TREATMENT
(a) Before applying the detailed requirements and
exemptions in these paragraphs, satisfactory weld procedure qualifications of the procedures to be used shall be
performed in accordance with all the essential variables of
Section IX including conditions of postweld heat treatment
or lack of postweld heat treatment and including other
restrictions listed below.
Except as otherwise specifically provided in the notes
to Table UCS-56 and Table UCS-56.1, all welds in pressure
2
See Appendix 1 of Section II, Part D for the basis on which the
allowable stress values have been established.
167
(10)
2010 SECTION VIII — DIVISION 1
vessels or pressure vessel parts shall be given a postweld
heat treatment at a temperature not less than specified in
those Tables when the nominal thickness, as defined in
UW-40(f), including corrosion allowance, exceeds the limits in those Tables. The exemptions provided in Table
UCS-56 or Table UCS-56.1 are not permitted when postweld heat treatment is a service requirement as set forth
in UCS-68, when welding ferritic materials greater than 1⁄8
in. (3 mm) thick with the electron beam welding process,
or when welding P-No. 3, P-No. 4, P-Nos. 5A, 5B, and
5C, P-No. 10, and P-No. 15E materials of any thickness
using the inertia and continuous drive friction welding
processes. Electroslag welds in ferritic materials over 11⁄2
in. (38 mm) thickness at the joint shall be given a grain
refining (austenitizing) heat treatment. Electrogas welds in
ferritic materials with any single pass greater than 11⁄2 in.
(38 mm) shall be given a grain refining (austenitizing) heat
treatment. For P-No. 1 materials only, the heating and
cooling rate restrictions of (d)(2) and (d)(5) below do not
apply when the heat treatment following welding is in the
austenitizing range.
The materials in Table UCS-56 are listed in accordance
with Section IX P-Number material groupings of QW-422
and also listed in Table UCS-23.
(b) Except where prohibited in Table UCS-56, holding
temperatures and /or holding times in excess of the minimum values given in Table UCS-56 may be used. Intermediate postweld heat treatments need not conform to the
requirements of Table UCS-56. The holding time at temperature as specified in Table UCS-56 need not be continuous. It may be an accumulation of time of multiple postweld
heat treatment cycles.
(c) When pressure parts of two different P-Number
groups are joined by welding, the postweld heat treatment
shall be that specified in either of Tables UCS-56 or
UHA-32, with applicable notes, for the material requiring
the higher postweld temperature. When nonpressure parts
are welded to pressure parts, the postweld heat treatment
temperature of the pressure part shall control.
(d) The operation of postweld heat treatment shall be
carried out by one of the procedures given in UW-40 in
accordance with the following requirements:
(1) The temperature of the furnace shall not exceed
800°F (425°C) at the time the vessel or part is placed in it.
(2) Above 800°F (425°C), the rate3 of heating shall
be not more than 400°F /hr (222°C / h) divided by the maximum metal thickness of the shell or head plate in inches,
but in no case more than 400°F /hr (222°C/h). During the
heating period there shall not be a greater variation in
temperature throughout the portion of the vessel being
heated than 250°F (140°C) within any 15 ft (4.6 m) interval
of length.
(3) The vessel or vessel part shall be held at or above
the temperature specified in Table UCS-56 or Table UCS56.1 for the period of time specified in the Tables. During
the holding period, there shall not be a greater difference
than 150°F (83°C) between the highest and lowest temperature throughout the portion of the vessel being heated,
except where the range is further limited in Table UCS-56.
(4) During the heating and holding periods, the furnace atmosphere shall be so controlled as to avoid excessive oxidation of the surface of the vessel. The furnace
shall be of such design as to prevent direct impingement
of the flame on the vessel.
(5) Above 800°F (425°C), cooling shall be done in
a closed furnace or cooling chamber at a rate3 not greater
than 500°F /hr (280°C /h) divided by the maximum metal
thickness of the shell or head plate in inches, but in no
case more than 500°F /hr (280°C /h). From 800°F (425°C)
the vessel may be cooled in still air.
(e) Except as permitted in (f) below, vessels or parts of
vessels that have been postweld heat treated in accordance
with the requirements of this paragraph shall again be
postweld heat treated after welded repairs have been made.
(f) Weld repairs to P-No. 1 Group Nos. 1, 2, and 3
materials and to P-No. 3 Group Nos. 1, 2, and 3 materials
and to the weld metals used to join these materials may
be made after the final PWHT but prior to the final hydrostatic test, without additional PWHT, provided that PWHT
is not required as a service requirement in accordance with
UW-2(a), except for the exemptions in Table UCS-56, or
as a service requirement in accordance with UCS-68. The
welded repairs shall meet the requirements of (1) through
(6) below. These requirements do not apply when the
welded repairs are minor restorations of the material surface, such as those required after removal of construction
fixtures, and provided that the surface is not exposed to
the vessel contents.
(1) The Manufacturer shall give prior notification of
the repair to the user or to his designated agent and shall
not proceed until acceptance has been obtained. Such
repairs shall be recorded on the Data Report.
(2) The total repair depth shall not exceed 11⁄2 in.
(38 mm) for P-No. 1 Group Nos. 1, 2, and 3 materials and
5
⁄8 in. (16 mm) for P-No. 3 Group Nos. 1, 2, and 3 materials.
The total depth of a weld repair shall be taken as the sum
of the depths for repairs made from both sides of a weld
at a given location.
(3) After removal of the defect, the groove shall be
examined, using either the magnetic particle or the liquid
penetrant examination methods, in accordance with Appendix 6 for MT and Appendix 8 for PT.
(4) In addition to the requirements of Section IX for
qualification of Welding Procedure Specifications for
3
The rates of heating and cooling need not be less than 100°F /hr
(56°C/h). However, in all cases consideration of closed chambers and
complex structures may indicate reduced rates of heating and cooling to
avoid structural damage due to excessive thermal gradients.
168
2010 SECTION VIII — DIVISION 1
TABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS
Material
P-No. 1
Gr. Nos. 1, 2, 3
Gr. No. 4
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
Normal Holding
Temperature,
°F (°C),
Minimum
Up to 2 in.
(50 mm)
Over 2 in. to 5 in.
(50 mm to 125 mm)
Over 5 in.
(125 mm)
1,100 (595)
1 hr/in. (25 mm),
15 min minimum
2 hr plus 15 min for
each additional inch
(25 mm) over 2 in.
(50 mm)
2 hr plus 15 min
for each additional inch (25
mm) over 2 in.
(50 mm)
NA
None
None
None
NOTES:
(1) When it is impractical to postweld heat treat at the temperature specified in this Table, it is permissible to carry out the postweld heat treatment
at lower temperatures for longer periods of time in accordance with Table UCS-56.1.
(2) Postweld heat treatment is mandatory under the following conditions:
(a) for welded joints over 11⁄2 in. (38 mm) nominal thickness;
(b) for welded joints over 11⁄4 in. (32 mm) nominal thickness through 11⁄2 in. (38 mm) nominal thickness unless preheat is applied at a
minimum temperature of 200°F (95°C) during welding;
(c) for welded joints of all thicknesses if required by UW-2, except postweld heat treatment is not mandatory under the conditions specified below:
(1) for groove welds not over 1⁄2 in. (13 mm) size and fillet welds with a throat not over 1⁄2 in. (13 mm) that attach nozzle connections
that have a finished inside diameter not greater than 2 in. (50 mm), provided the connections do not form ligaments that require
an increase in shell or head thickness, and preheat to a minimum temperature of 200°F (95°C) is applied;
(2) for groove welds not over 1⁄2 in. (13 mm) in size or fillet welds with a throat thickness of 1⁄2 in. (13 mm) or less that attach tubes
to a tubesheet when the tube diameter does not exceed 2 in. (50 mm). A preheat of 200°F (95°C) minimum must be applied when
the carbon content of the tubesheet exceeds 0.22%.
(3) for groove welds not over 1⁄2 in. (13 mm) in size or fillet welds with a throat thickness of 1⁄2 in. (13 mm) or less used for attaching
nonpressure parts to pressure parts provided preheat to a minimum temperature of 200°F (95°C) is applied when the thickness of
the pressure part exceeds 11⁄4 in. (32 mm);
(4) for studs welded to pressure parts provided preheat to a minimum temperature of 200°F (95°C) is applied when the thickness of
the pressure part exceeds 11⁄4 in. (32 mm);
(5) for corrosion resistant weld metal overlay cladding or for welds attaching corrosion resistant applied lining (see UCL-34) provided
preheat to a minimum temperature of 200°F (95°C) is maintained during application of the first layer when the thickness of the
pressure part exceeds 11⁄4 in. (32 mm).
NA p not applicable
169
2010 SECTION VIII — DIVISION 1
TABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS (CONT’D)
Material
P-No. 3
Gr. Nos. 1, 2, 3
Normal Holding
Temperature,
°F (°C),
Minimum
1,100 (595)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
Up to 2 in.
(50 mm)
Over 2 in. to 5 in.
(50 mm to 125 mm)
Over 5 in.
(125 mm)
1 hr/in. (25 mm),
15 min minimum
2 hr plus 15 min for
each additional
inch (25 mm)
over 2 in.
(50 mm)
2 hr plus 15 min
for each additional inch (25
mm) over 2 in.
(50 mm)
NOTES:
(1) When it is impractical to postweld heat treat at the temperatures specified in this Table, it is permissible to carry out the postweld heat
treatment at lower temperatures for longer periods of time in accordance with Table UCS-56.1.
(2) Postweld heat treatment is mandatory on P-No. 3 Gr. No. 3 material in all thicknesses.
(3) Except for the exemptions in Note (4), postweld heat treatment is mandatory under the following conditions:
(a) on P-No. 3 Gr. No. 1 and P-No. 3 Gr. No. 2 over 5⁄8 in. (16 mm) nominal thickness. For these materials, postweld heat treatment is
mandatory on material up to and including 5⁄8 in. (16 mm) nominal thickness unless a welding procedure qualification described in UCS56(a) has been made in equal or greater thickness than the production weld.
(b) on material in all thicknesses if required by UW-2.
(4) For welding connections and attachments to pressure parts, postweld heat treatment is not mandatory under the conditions specified below:
(a) for attaching to pressure parts that have a specified maximum carbon content of not more than 0.25% (SA material specification carbon
content, except when further limited by the purchaser to a value within the specification limits) or nonpressure parts with groove welds
not over 1⁄2 in. (13 mm) in size or fillet welds that have a throat thickness of 1⁄2 in. (13 mm) or less, provided preheat to a minimum
temperature of 200°F (95°C) is applied;
(b) for circumferential butt welds in pipe or tube where the pipe or tube have both a nominal wall thickness of 1⁄2 in. (13 mm) or less and
a specified maximum carbon content of not more than 0.25% (SA material specification carbon content, except when further limited
by the purchaser to a value within the specification limits);
(c) for studs welded to pressure parts that have a specified maximum carbon content of not more than 0.25% (SA material specification
carbon content, except when further limited by the purchaser to a value within the specification limits) provided preheat to a minimum
temperature of 200°F (95°C) is applied;
(d) for corrosion resistant weld metal overlay cladding or for welds attaching corrosion resistant applied lining (see UCL-34) when welded
to pressure parts which have a specified maximum carbon content of not more than 0.25% (SA material specification carbon content,
except when further limited by the purchaser to a value within the specification limits) provided preheat to a minimum temperature of
200°F (95°C) is maintained during application of the first layer.
170
2010 SECTION VIII — DIVISION 1
TABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS (CONT’D)
Material
P-No. 4
Gr. Nos. 1, 2
Normal Holding
Temperature,
°F (°C),
Minimum
1,200 (650)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
Up to 2 in.
(50 mm)
1 hr/in. (25 mm),
15 min minimum
Over 2 in. to 5 in.
(50 mm to 125 mm)
1 hr/in. (25 mm)
Over 5 in.
(125 mm)
5 hr plus 15 min
for each additional inch (25
mm) over 5 in.
(125 mm)
NOTES:
(1) Except for exemptions in Note (2), postweld heat treatment is mandatory under the following conditions:
(a) on material of SA-202 Grades A and B over 5⁄8 in. (16 mm) nominal thickness. For these materials postweld heat treatment is mandatory
up to and including 5⁄8 in. (16 mm) nominal thickness unless a welding procedure qualification described in UCS-56(a) has been made
in equal or greater thickness than the production weld.
(b) on material of all thicknesses if required by UW-2;
(c) on all other P-No. 4 Gr. Nos. 1 and 2 materials.
(2) Postweld heat treatment is not mandatory under the conditions specified below:
(a) for circumferential butt welds in pipe or tube of P-No. 4 materials where the pipe or tubes comply with all of the following conditions:
(1) a maximum nominal outside diameter of 4 in. (100mm) (DN 100);
(2) a maximum nominal thickness of 5⁄8 in. (16 mm);
(3) a maximum specified carbon content of not more than 0.15% (SA material specification carbon content, except when further limited
by the purchaser to a value within the specification limits);
(4) a minimum preheat of 250°F (120°C).
(b) for P-No. 4 pipe or tube materials meeting the requirements of (2)(a)(1), (2)(a)(2), and (2)(a)(3) above, having nonpressure attachments
fillet welded to them provided:
(1) the fillet welds have a maximum throat thickness of 1⁄2 in. (13 mm);
(2) a minimum preheat temperature of 250°F (120°C) is applied.
(c) for P-No. 4 pipe or tube materials meeting the requirements of (2)(a)(1), (2)(a)(2), and (2)(a)(3) above, having studs welded to them,
a minimum preheat temperature of 250°F (120°C) is applied.
(d) for P-No. 4 pipe or tube materials meeting the requirements of (2)(a)(1) and (2)(a)(3), above, having extended heat absorbing fins
electrically resistance-welded to them provided:
(1) the fins have a maximum thickness of 1⁄8 in. (3 mm);
(2) prior to using the welding procedure, the Manufacturer shall demonstrate that the heat-affected zone does not encroach upon the
minimum pipe or tube wall thickness.
171
2010 SECTION VIII — DIVISION 1
TABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS (CONT’D)
Material
P-Nos. 5A, 5B Gr. No. 1,
and 5C Gr. No. 1
Normal Holding
Temperature,
°F (°C),
Minimum
1,250 (675)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
Up to 2 in.
(50 mm)
1 hr/in. (25 mm),
15 min minimum
Over 2 in. to 5 in.
(50 mm to 125 mm)
1 hr/in. (25 mm)
Over 5 in.
(125 mm)
5 hr plus 15 min
for each additional inch
(25 mm) over
5 in. (125
mm)
NOTES:
(1) Except for exemptions in Note (2), postweld heat treatment is mandatory under all conditions.
(2) Postweld heat treatment is not mandatory under the following conditions:
(a) for circumferential butt welds in pipe or tube where the pipe or tubes comply with all of the following conditions:
(1) a maximum specified chromium content of 3.00%;
(2) a maximum nominal outside diameter of 4 in. (100 mm) (DN 100);
(3) a maximum nominal thickness of 5⁄8 in. (16 mm);
(4) a maximum specified carbon content of not more than 0.15% (SA material specification carbon content, except when further limited
by the purchaser to a value within the specification limits);
(5) a minimum preheat of 300°F (150°C) is applied.
(b) for pipe or tube materials meeting the requirements of (2)(a)(1), (2)(a)(2), (2)(a)(3), and (2)(a)(4) having nonpressure attachments
fillet welded to them provided:
(1) the fillet welds have a maximum throat thickness of 1⁄2 in. (13 mm);
(2) a minimum preheat temperature of 300°F (150°C) is applied.
(c) for pipe or tube materials meeting the requirements of (2)(a)(1), (2)(a)(2), (2)(a)(3), and (2)(a)(4) having studs welded to them provided
a minimum preheat temperature of 300°F (150°C) is applied.
(d) for pipe or tube materials meeting the requirements of (2)(a)(1) and (2)(a)(3), above, having extended heat absorbing fins electrically
resistance-welded to them provided:
(1) the fins have a maximum thickness of 1⁄8 in. (3 mm);
(2) prior to using the welding procedure, the Manufacturer shall demonstrate that the heat-affected zone does not encroach upon the
minimum pipe or tube wall thickness.
(3) When it is impractical to postweld heat P-Nos. 5A, 5B Gr. No. 1, and 5C Gr. No. 1 materials at the temperature specified in this Table, it
is permissible to perform the postweld heat treatment at 1,200°F (650°C) minimum provided that, for material up to 2 in. (50 mm) nominal
thickness, the holding time is increased to the greater of 4 hr minimum or 4 hr/in. (25 mm) of thickness; for thickness over 2 in. (50 mm),
the specified holding times are multiplied by 4. The requirements of UCS-85 must be accommodated in this reduction in postweld heat treatment.
172
2010 SECTION VIII — DIVISION 1
TABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS (CONT’D)
Material
P-No.
15E
Group
No. 1
Minimum
Holding
Temperature, °F (°C)
[Notes (1)
and (2)]
Maximum
Holding
Temperature,
°F (°C)
[Notes (3)
and (4)]
1,350 (730)
1,425 (775)
Minimum Holding Time at Normal Temperature
for Weld Thickness (Nominal)
Up to 5 in.
(125 mm)
1 hr/in.
(2 min/mm),
30 min
minimum
Over 5 in.
(125 mm)
5 hr plus 15 min for each additional
inch (25 mm) over 5 in. (125 mm)
NOTES:
(1) If the nominal weld thickness is ≤ 0.5 in. (13 mm), the minimum holding temperature is 1,325°F (720°C).
(2) For dissimilar metal welds (i.e., welds made between a P-No. 15E Group No. 1 and another lower chromium ferritic, austenitic, or nickelbased steel), if filler metal chromium content is less than 3.0% or if the filler metal is nickel-based or austenitic, the minimum holding
temperature shall be 1,300°F (705°C).
(3) The maximum holding temperature above is to be used if the actual chemical composition of the matching filler metal used when making the
weld is unknown. If the chemical composition of the matching filler metal is known, the maximum holding temperature can be increased as
follows:
(a) If Ni + Mn < 1.50% but ≥ 1.0%, the maximum PWHT temperature is 1,450°F (790°C).
(b) If Ni + Mn < 1.0%, the maximum PWHT temperature is 1,470°F (800°C).
Explanatory Note to (3) Above: The lower transformation temperature for matching filler material is affected by alloy content, primarily the
total of Ni + Mn. The maximum holding temperature has been set to avoid heat treatment in the intercritical zone.
(4) If a portion of the component is heated above the heat treatment temperature allowed above, one of the following actions shall be performed:
(a) The component in its entirety must be renormalized and tempered.
(b) If the maximum holding temperature in the Table or Note (3)(a) above is exceeded, but does not exceed 1,470°F (800°C), the weld
metal shall be removed and replaced.
(c) The portion of the component heated above 1,470°F (800°C) and at least 3 in. (75 mm) on either side of the overheated zone must be
removed and be renormalized and tempered or replaced.
(d) The allowable stress shall be that for Grade 9 material (i.e., SA-213-T9, SA-335-P9, or equivalent product specification) at the design
temperature, provided that the portion of the component heated to a temperature greater than that allowed above is reheat treated within
the temperature range specified above.
(5) Postweld heat treatment is not mandatory for electric resistance welds used to attach extended heat-absorbing fins to pipe and tube materials,
provided the following requirements are met:
(a) a maximum pipe or tube size of NPS 4 (DN 100)
(b) a maximum specified carbon content (SA material specification carbon content, except when further limited by the Purchaser to a value
within the specification limits) of not more than 0.15%
(c) a maximum fin thickness of 1⁄8 in. (3 mm)
(d) prior to using the welding procedure, the Manufacturer shall demonstrate that the heat-affected zone does not encroach upon the minimum
wall thickness
173
2010 SECTION VIII — DIVISION 1
TABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS (CONT’D)
Material
P-No. 9A Gr. No. 1
Normal Holding
Temperature,
°F (°C),
Minimum
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
1,100 (595)
1 hr minimum, plus 15 min/in. (25 mm) for
thickness over 1 in. (25 mm)
NOTES:
(1) When it is impractical to postweld heat treat at the temperature specified in this Table, it is permissible to carry out the postweld heat treatment
at lower temperatures [1,000°F (540°C) minimum] for longer periods of time in accordance with Table UCS-56.1.
(2) Except for exemptions in Note (3), postweld heat treatment is mandatory under the following conditions:
(a) on material over 5⁄8 in. (16 mm) nominal thickness. For material up to and including 5⁄8 in. (16 mm) nominal thickness, postweld heat
treatment is mandatory unless a welding procedure qualification described in UCS-56(a) has been made in equal or greater thickness
than the production weld.
(b) on material of all thicknesses if required by UW-2.
(3) Postweld heat treatment is not mandatory under conditions specified below:
(a) for circumferential butt welds in pipe or tubes where the pipe or tubes comply with all the following conditions:
(1) a maximum nominal outside diameter of 4 in. (100 mm) (DN 100);
(2) a maximum thickness of 1⁄2 in. (13 mm);
(3) a maximum specified carbon content of not more than 0.15% (SA material specification carbon content, except when further limited
by the purchaser to a value within the specification limits);
(4) a minimum preheat of 250°F (120°C).
(b) for pipe or tube materials meeting the requirements of (3)(a)(1), (3)(a)(2), and (3)(a)(3) above, having attachments fillet welded to
them, provided:
(1) the fillet welds have a throat thickness of 1⁄2 in. (13 mm) or less;
(2) the material is preheated to 250°F (120°C) minimum. A lower preheating temperature may be used provided specifically controlled
procedures necessary to produce sound welded joints are used. Such procedures shall include but shall not be limited to the following:
(a) The throat thickness of fillet welds shall be 1⁄2 in. (13 mm) or less.
(b) The maximum continuous length of fillet welds shall be not over 4 in. (100 mm).
(c) The thickness of the test plate used in making the welding procedure qualification of Section IX shall not be less than that of
the material to be welded.
(c) for attaching nonpressure parts to pressure parts with groove welds not over 1⁄2 in. (13 mm) in size or fillet welds that have a throat
thickness of 1⁄2 in. (13 mm) or less, provided preheat to a minimum temperature of 200°F (95°C) is applied;
(d) for studs welded to pressure parts provided preheat to a minimum temperature of 200°F (95°C) is applied;
(e) for corrosion resistant weld metal overlay cladding or for welds attaching corrosion resistant applied lining (see UCL-34) provided preheat
to a minimum temperature of 200°F (95°C) is maintained during application of the first layer.
(4) When the heating rate is less than 50°F (28°C)/hr between 800°F (425°C) and the holding temperature, the additional 15 min/in. (25 mm)
holding time is not required. Additionally, where the Manufacturer can provide evidence that the minimum temperature has been achieved
throughout the thickness, the additional 15 min/in. (25 mm) holding time is not required.
174
2010 SECTION VIII — DIVISION 1
TABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS (CONT’D)
Material
P-No. 9B
Gr. No. 1
Normal Holding Temperature,
°F (°C), Minimum
1,100 (595)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
1 hr minimum, plus 15 min/in. (25 mm) for
thickness over 1 in. (25 mm)
NOTES:
(1) When it is impractical to postweld heat treat at the temperatures specified in this Table, it is permissible to carry out the postweld heat
treatment at lower temperatures [1,000°F (540°C) minimum] for longer periods of time in accordance with Table UCS-56.1.
(2) The holding temperature for postweld heat treatment shall not exceed 1,175°F (635°C).
(3) Except for exemptions in Note (4), postweld heat treatment is mandatory under the following conditions:
(a) on material over 5⁄8 in. (16 mm) nominal thickness. For material up to and including 5⁄8 in. (16 mm) nominal thickness, postweld heat
treatment is mandatory unless a welding procedure qualification described in UCS-56(a) has been made in equal or greater thickness
than the production weld.
(b) on material of all thicknesses if required by UW-2.
(4) Postweld heat treatment is not mandatory under the conditions specified below:
(a) for attaching nonpressure parts to pressure parts with groove welds not over 1⁄2 in. (13 mm) in size or fillet welds that have a throat
thickness of 1⁄2 in. (13 mm) or less, provided preheat to a minimum temperature of 200°F (95°C) is applied;
(b) for studs welded to pressure parts provided preheat to a minimum temperature of 200°F (95°C) is applied;
(c) for corrosion resistant weld metal overlay cladding or for welds attaching corrosion resistant applied lining (see UCL-34) provided preheat
to a minimum temperature of 200°F (95°C) is maintained during application of the first layer.
(5) When the heating rate is less than 50°F (28°C)/hr between 800°F (425°C) and the holding temperature, the additional 15 min/in. (25 mm)
holding time is not required. Additionally, where the Manufacturer can provide evidence that the minimum temperature has been achieved
throughout the thickness, the additional 15 min/in. (25 mm) holding time is not required.
Material
P-No. 10A
Gr. No. 1
Normal Holding Temperature,
°F (°C), Minimum
1,100 (595)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
1 hr minimum, plus 15 min/in. (25 mm) for
thickness over 1 in. (25 mm)
NOTES:
(1) (a) When it is impractical to postweld heat treat at the temperature specified in this Table, it is permissible to carry out the postweld heat
treatment at lower temperatures for longer periods of time in accordance with Table UCS-56.1.
(b) Consideration should be given for possible embrittlement of materials containing up to 0.15% vanadium when postweld heat treating at
the minimum temperature and at lower temperature for longer holding times.
(2) Except for exemptions in Note (3), postweld heat treatment is mandatory under the following conditions:
(a) on all thicknesses of SA-487 Class 1Q material;
(b) on all other P-No. 10A materials over 5⁄8 in. (16 mm) nominal thickness. For these materials up to and including 5⁄8 in. (16 mm) nominal
thickness, postweld heat treatment is mandatory unless a welding procedure qualification described in UCS-56(a) has been made in equal
or greater thickness than the production weld.
(c) on material of all thicknesses if required by UW-2.
(3) Postweld heat treatment is not mandatory under the conditions specified below:
(a) for attaching to pressure parts that have a specified maximum carbon content of not more than 0.25% (SA material specification carbon
content, except when further limited by the purchaser to a value within the specification limits) or nonpressure parts with groove weld
not over 1⁄2 in. (13 mm) in size or fillet welds having a throat thickness of 1⁄2 in. (13 mm) or less, provided preheat to a minimum
temperature of 200°F (95°C) is applied;
(b) for circumferential butt welds in pipes or tube where the pipe or tube has both a nominal wall thickness of 1⁄2 in. (13 mm) or less and
a specified maximum carbon content of not more than 0.25% (SA material specification carbon content, except when further limited
by purchaser to a value within the specification limits) provided preheat to a minimum temperature of 200°F (95°C) is applied;
(c) for studs welded to pressure parts that have a specified maximum carbon content of not more than 0.25% (SA material specification
carbon content, except when further limited by purchaser to a value within the specification limits) provided preheat to a minimum
temperature of 200°F (95°C) is applied;
(d) for corrosion resistant weld metal overlay cladding or for welds attaching corrosion resistant applied lining (see UCL-34) when welded
to pressure parts that have a specified maximum carbon content of not more than 0.25% (SA material specification carbon content,
except when further limited by the purchaser to a value within the specification limits) provided preheat to a minimum temperature of
200°F (95°C) is maintained during application of the first layer.
(4) When the heating rate is less than 50°F (28°C)/hr between 800°F (425°C) and the holding temperature, the additional 15 min/in. (25 mm)
holding time is not required. Additionally, where the Manufacturer can provide evidence that the minimum temperature has been achieved
throughout the thickness, the additional 15 min/in. (25 mm) holding time is not required.
175
(10)
2010 SECTION VIII — DIVISION 1
(10)
TABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS (CONT’D)
Material
P-No. 10B
Gr. No. 1
Normal Holding Temperature,
°F (°C), Minimum
1,100 (595)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
1 hr minimum, plus 15 min/in. (25 mm) for
thickness over 1 in. (25 mm)
NOTES:
(1) Postweld heat treatment is mandatory for P-No. 10B materials for all thicknesses.
(2) When the heating rate is less than 50°F (28°C)/hr between 800°F (425°C) and the holding temperature, the additional 15 min/in. (25 mm)
holding time is not required. Additionally, where the Manufacturer can provide evidence that the minimum temperature has been achieved
throughout the thickness, the additional 15 min/in. (25 mm) holding time is not required.
Material
P-No. 10C
Gr. No. 1
Normal Holding Temperature,
°F (°C), Minimum
1,000 (540)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
1 hr minimum, plus 15 min/in. (25 mm) for
thickness over 1 in. (25 mm)
NOTES:
(1) When it is impractical to postweld heat treat at the temperatures specified in this Table, it is permissible to carry out the postweld heat
treatment at lower temperatures for longer periods of time in accordance with Table UCS-56.1.
(2) Except for exemptions in Note (3), postweld heat treatment is mandatory under the following conditions:
(a) for material over 11⁄2 in. (38 mm) nominal thickness. Postweld heat treatment is mandatory on materials over 11⁄4 in. (32 mm) nominal
thickness through 11⁄2 in. (38 mm) nominal thickness unless preheat is applied at a minimum temperature of 200°F (95°C) during
welding.
(b) on material of all thicknesses if required by UW-2.
(3) Postweld heat treatment is not mandatory under the conditions specified below:
(a) for groove welds not over 1⁄2 in. (13 mm) in size and fillet welds with throat not over 1⁄2 in. (13 mm) that attach nozzle connections that
have a finished inside diameter not greater than 2 in. (50 mm) provided the connections do not form ligaments that require an increase
in shell or head thickness and preheat to a minimum temperature of 200°F (95°C) is applied;
(b) for groove welds not over 1⁄2 in. (13 mm) in size or fillet welds having throat thickness of 1⁄2 in. (13 mm) or less used for attaching
nonpressure parts to pressure parts and preheat to a minimum temperature of 200°F (95°C) is applied when the thickness of the pressure
part exceeds 11⁄4 in. (32 mm);
(c) for studs welded to pressure parts provided preheat to a minimum temperature of 200°F (95°C) is applied when the thickness of the
pressure part exceeds 11⁄4 in. (32 mm);
(d) for corrosion resistant weld metal overlay cladding or for welds attaching corrosion resistant applied lining (see UCL-34) provided preheat
to a minimum temperature of 200°F (95°C) is maintained during application of the first layer when the thickness of the pressure part
exceeds 11⁄4 in. (32 mm).
(4) When the heating rate is less than 50°F (28°C)/hr between 800°F (425°C) and the holding temperature, the additional 15 min/in. (25 mm)
holding time is not required. Additionally, where the Manufacturer can provide evidence that the minimum temperature has been achieved
throughout the thickness, the additional 15 min/in. (25 mm) holding time is not required.
Material
P-No. 10F
Gr. No. 1
Normal Holding Temperature,
°F (°C), Minimum
1,000 (540)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
1 hr minimum, plus 15 min/in. (25 mm) for
thickness over 1 in. (25 mm)
NOTES:
(1) Postweld heat treatment is mandatory for P-No. 10F materials for all thicknesses.
(2) When the heating rate is less than 50°F (28°C)/hr between 800°F (425°C) and the holding temperature, the additional 15 min/in. (25 mm)
holding time is not required. Additionally, where the Manufacturer can provide evidence that the minimum temperature has been achieved
throughout the thickness, the additional 15 min/in. (25 mm) holding time is not required.
176
2010 SECTION VIII — DIVISION 1
TABLE UCS-56.1
ALTERNATIVE POSTWELD HEAT TREATMENT
REQUIREMENTS FOR CARBON
AND LOW ALLOY STEELS
Applicable Only When Permitted in Table UCS-56
Decrease in
Temperature
Below Minimum
Specified
Temperature, °F
(°C)
50
100
150
200
(28)
(56)
(83)
(111)
TABLE UCS-57
THICKNESS ABOVE WHICH FULL RADIOGRAPHIC
EXAMINATION OF BUTT WELDED JOINTS IS
MANDATORY
P-No. & Group No.
Classification of
Material
Minimum Holding
Time [Note (1)]
at Decreased
Temperature, hr
Notes
2
4
10
20
...
...
(2)
(2)
11⁄4 (32)
3
⁄4 (19)
5
⁄8 (16)
0 (0)
0 (0)
0 (0)
0 (0)
1 Gr. 1, 2, 3
3 Gr. 1, 2, 3
4 Gr. 1, 2
5A Gr. 1, 2
5B Gr. 1
5C Gr. 1
15E, Gr. 1
5
9A Gr. 1
9B Gr. 1
10A Gr. 1
10B Gr. 1
10C Gr. 1
10F Gr. 1
NOTES:
(1) Minimum holding time for 1 in. (25 mm) thickness or less. Add
15 minutes per inch (25 mm) of thickness for thicknesses greater
than 1 in. (25 mm).
(2) These lower postweld heat treatment temperatures permitted only
for P-No. 1 Gr. Nos. 1 and 2 materials.
groove welds, the following requirements shall apply:
(a) The weld metal shall be deposited by the manual shielded metal arc process using low hydrogen electrodes. The electrodes shall be properly conditioned in
accordance with Section II, Part C, SFA-5.5, Appendix
A6.11. The maximum bead width shall be four times the
electrode core diameter.
(b) For P-No. 1 Group Nos. 1, 2, and 3 materials,
the repair area shall be preheated and maintained at a
minimum temperature of 200°F (95°C) during welding.
(c) For P-No. 3 Group Nos. 1, 2, and 3 materials,
the repair weld method shall be limited to the half bead
weld repair and weld temper bead reinforcement technique.
The repair area shall be preheated and maintained at a
minimum temperature of 350°F (175°C) during welding.
The maximum interpass temperature shall be 450°F
(230°C). The initial layer of weld metal shall be deposited
over the entire area using 1⁄8 in. (3 mm) maximum diameter
electrodes. Approximately one-half the thickness of this
layer shall be removed by grinding before depositing subsequent layers. The subsequent weld layers shall be deposited
using 5⁄32 in. (4 mm) maximum diameter electrodes in such
a manner as to assure tempering of the prior weld beads
and their heat affected zones. A final temper bead weld
shall be applied to a level above the surface being repaired
without contacting the base material but close enough to
the edge of the underlying weld bead to assure tempering
of the base material heat affected zone. After completing
all welding, the repair area shall be maintained at a temperature of 400°F–500°F (205°C–260°C) for a minimum period
of 4 hr. The final temper bead reinforcement layer shall
be removed substantially flush with the surface of the base
material.
Nominal Thickness Above Which
Butt Welded Joints Shall Be
Fully Radiographed, in. (mm)
⁄8
⁄8
3
⁄4
5
⁄8
5
⁄8
3
⁄4
5
(16)
(16)
(19)
(16)
(16)
(19)
(5) After the finished repair weld has reached ambient
temperature, it shall be inspected using the same nondestructive examination that was used in (f)(3) above, except
that for P-No. 3, Group No. 3 materials, the examination
shall be made after the material has been at ambient temperature for a minimum period of 48 hr to determine the
presence of possible delayed cracking of the weld. If the
examination is by the magnetic particle method, only the
alternating current yoke type is acceptable. In addition,
welded repairs greater than 3⁄8 in. (10 mm) deep in materials
and in welds that are required to be radiographed by the
rules of this Division, shall be radiographically examined
to the requirements of UW-51.
(6) The vessel shall be hydrostatically tested after
making the welded repair.
UCS-57
RADIOGRAPHIC EXAMINATION
In addition to the requirements of UW-11, complete
radiographic examination is required for each butt welded
joint at which the thinner of the plate or vessel wall thicknesses at the welded joint exceeds the thickness limit above
which full radiography is required in Table UCS-57.
LOW TEMPERATURE OPERATION
UCS-65
SCOPE
The following paragraphs contain requirements for vessels and vessel parts constructed of carbon and low alloy
steels with respect to minimum design metal temperatures.
177
2010 SECTION VIII — DIVISION 1
UCS-66
flange thickness divided by 4 or the minimum thickness
of the dished portion.
(5) If the governing thickness of the nonwelded part
exceeds 6 in. (150 mm) and the minimum design metal
temperature is colder than 120°F (50°C), impact tested
material shall be used.
MATERIALS
(a) Unless exempted by the rules of UG-20(f) or
other rules of this Division, Fig. UCS-66 shall be used to
establish impact testing exemptions for steels listed
in Part UCS. When Fig. UCS-66 is used, impact testing
is required for a combination of minimum design metal
temperature (see UG-20) and thickness (as defined below)
which is below the curve assigned to the subject material.
If a minimum design metal temperature and thickness combination is on or above the curve, impact testing is not
required by the rules of this Division, except as required
by (j) below and UCS-67(a)(2) for weld metal.
Components, such as shells, heads, nozzles, manways,
reinforcing pads, flanges, tubesheets, flat cover plates,
backing strips which remain in place, and attachments
which are essential to the structural integrity of the vessel
when welded to pressure retaining components, shall be
treated as separate components. Each component shall be
evaluated for impact test requirements based on its individual material classification, thickness as defined in (1), (2),
or (3) below, and the minimum design metal temperature.
The following thickness limitations apply when using
Fig. UCS-66:
(1) Excluding castings, the governing thickness tg of
a welded part is as follows:
(a) for butt joints except those in flat heads and
tubesheets, the nominal thickness of the thickest welded
joint [see Fig. UCS-66.3 sketch (a)];
(b) for corner, fillet, or lap welded joints, including
attachments as defined above, the thinner of the two parts
joined;
(c) for flat heads or tubesheets, the larger of (b)
above or the flat component thickness divided by 4;
(d) for welded assemblies comprised of more than
two components (e.g., nozzle-to-shell joint with reinforcing
pad), the governing thickness and permissible minimum
design metal temperature of each of the individual welded
joints of the assembly shall be determined, and the warmest
of the minimum design metal temperatures shall be used
as the permissible minimum design metal temperature of
the welded assembly. [See Fig. UCS-66.3 sketch (b),
L-9.3.1, and L-9.5.2.]
Examples of the governing thickness for some typical vessel details are shown in Fig. UCS-66.3.
NOTE: The use of provisions in UCS-66 which waive the requirements
for impact testing does not provide assurance that all test results for these
materials would satisfy the impact energy requirements of UG-84 if tested.
(b) When the coincident ratio defined in Fig. UCS-66.1
is less than one, Fig. UCS-66.1 provides a basis for the
use of components made of Part UCS materials to have a
colder MDMT than that derived from (a) above without
impact testing.
(1)(a) For such components, and for a MDMT of
−55°F (−48°C) and warmer, the MDMT without impact
testing determined in (a) above for the given material and
thickness may be reduced as determined from
Fig. UCS-66.2. If the resulting temperature is colder than
the required MDMT, impact testing of the material is not
required.
(b) Figure UCS-66.1 may also be used for components not stressed in general primary membrane tensile
stress, such as flat heads, covers, tubesheets, and flanges
(including bolts and nuts). The MDMT of these components without impact testing as determined in UCS-66(a)
or (c) may be reduced as determined from Fig. UCS-66.2.
The ratio used in Step 3 of Fig. UCS-66.2 shall be the
ratio of maximum design pressure at the MDMT to the
maximum allowable pressure (MAP) of the component at
the MDMT. If the resulting temperature is colder than
the required MDMT, impact testing of the material is not
required, provided the MDMT is not colder than −55°F
(−48°C).
(c) In lieu of using (b)(1)(b) above, the MDMT
determined in UCS-66(a) or (c) may be reduced for a flange
attached by welding, by the same reduction as determined
in (b)(1)(a) above for the neck or shell which the flange
is attached.
If the governing thickness at any welded joint exceeds 4 in.
and the minimum design metal temperature is colder than
120°F (50°C), impact tested material shall be used.
(2) The governing thickness of a casting shall be its
largest nominal thickness.
(3) The governing thickness of flat nonwelded parts,
such as bolted flanges, tubesheets, and flat heads, is the
flat component thickness divided by 4.
(4) The governing thickness of a nonwelded dished
head [see Fig. 1-6 sketch (c)] is the greater of the flat
NOTE: The bolt-up condition need not be considered when determining
the temperature reduction for flanges.
(2) For minimum design metal temperatures colder
than −55°F (−48°C), impact testing is required for all materials, except as allowed in (b)(3) below and in UCS-68(c).
(3) When the minimum design metal temperature is
colder than −55°F (−48°C) and no colder than −155°F
(−105°C), and the coincident ratio defined in Fig. UCS-66.1
is less than or equal to 0.35, impact testing is not required.
178
2010 SECTION VIII — DIVISION 1
FIG. UCS-66 IMPACT TEST EXEMPTION CURVES
160
140
120
100
A [Note (1)]
Minimum Design Metal Temperature, ºF
B [Note (2)]
80
60
C [Note (3)]
40
D [Note (4)]
20
0
-20
-40
-55
-60
Impact testing required
-80
0.394
1
2
3
4
Nominal Thickness, in.
[Limited to 4 in. for Welded Construction]
GENERAL NOTES:
(a) Tabular values for this figure are provided in Table UCS-66.
(b) See UCS-66(a).
179
5
6
2010 SECTION VIII — DIVISION 1
FIG. UCS-66 IMPACT TEST EXEMPTION CURVES (CONT’D)
GENERAL NOTES (CONT’D):
(c) For bolting and nuts, the following impact test exemption temperatures shall apply:
Bolting
Spec. No.
Grade
Impact Test Exemption
Temperature, °F (°C)
Diameter, in. (mm)
SA-193
B5
B7
...
B7M
B16
Up to 4 (100), incl.
Up to 21⁄2 in. (64), incl.
Over 21⁄2 (64) to 7 (175), incl.
Up to 21⁄2 (64), incl.
Up to 7 (175), incl.
−20
−55
−40
−55
−20
SA-307
SA-320
SA-325
SA-354
SA-354
B
L7, L7A, L7M
L43
1
BC
BD
All
Up to 21⁄2 (64), incl.
Up to 1 (25), incl.
1
⁄2 (13) to 11⁄2 (38)
Up to 4 (100), incl.
Up to 4 (100), incl.
−20 (−30)
See General Note (c) of Fig. UG-84.1
See General Note (c) of Fig. UG-84.1
−20 (−30)
0 (−18)
+20 (−7)
SA-437
SA-449
SA-540
SA-540
B4B, B4C
...
B21 Cl. All
B22 Cl. 3
All diameters
Up to 3 (75), incl.
All
Up to 4 (100), incl.
See General Note (c) of Fig. UG-84.1
−20 (−30)
Impact test required
Impact test required
SA-540
SA-540
SA-540
SA-540
SA-540
B23 Cl. 1, 2
B23 Cl. 3, 4
B23 Cl. 3, 4
B23 Cl. 5
B23 Cl. 5
All
Up to 6 (150), incl.
Over 6 (150) to 91⁄2 (240), incl.
Up to 8 (200), incl.
Over 8 (200) to 91⁄2 (240), incl.
Impact test required
See General Note (c) of Fig. UG-84.1
Impact test required
See General Note (c) of Fig. UG-84.1
Impact test required
SA-540
SA-540
SA-540
SA-540
B24
B24
B24
B24
Up to 6 (150), incl.
Over 6 (150) to 8 (200), incl.
Up to 7 (175), incl.
Over 7 (175) to 91⁄2 (240), incl.
See General Note (c) of Fig. UG-84.1
Impact test required
See General Note (c) of Fig. UG-84.1
Impact test required
SA-540
SA-540
SA-540
SA-540
B24 Cl. 3, 4
B24 Cl. 3, 4
B24 Cl. 5
B24V Cl. 3
Up to 8 (200), incl.
Over 8 (200) to 91⁄2 (240), incl.
Up to 91⁄2 (240), incl.
All
See General Note (c) of Fig. UG-84.1
Impact test required
See General Note (c) of Fig. UG-84.1
See General Note (c) of Fig. UG-84.1
Cl.
Cl.
Cl.
Cl.
1
1
2
2
(−30)
(−48)
(−40)
(−48)
(−30)
Nuts
Spec. No.
SA-194
SA-540
Grade
Impact Test Exemption
Temperature, °F (°C)
2, 2H, 2HM, 3, 4, 7, 7M, and 16
B21/B22/B23/B24/B24V
−55 (−48)
−55 (−48)
(d) When no class or grade is shown, all classes or grades are included.
(e) The following shall apply to all material assignment notes:
(1) Cooling rates faster than those obtained by cooling in air, followed by tempering, as permitted by the material specification, are
considered to be equivalent to normalizing or normalizing and tempering heat treatments.
(2) Fine grain practice is defined as the procedure necessary to obtain a fine austenitic grain size as described in SA-20.
(3) Normalized rolling condition is not considered as being equivalent to normalizing.
(f) Castings not listed in Notes (1) and (2) below shall be impact tested.
180
2010 SECTION VIII — DIVISION 1
FIG. UCS-66 IMPACT TEST EXEMPTION CURVES (CONT’D)
NOTES:
(1) Curve A applies to:
(a) all carbon and all low alloy steel plates, structural shapes, and bars not listed in Curves B, C, and D below;
(b) SA-216 Grades WCB and WCC if normalized and tempered or water-quenched and tempered; SA-217 Grade WC6 if normalized and
tempered or water-quenched and tempered.
(2) Curve B applies to:
(a) SA-216 Grade WCA if normalized and tempered or water-quenched and tempered
SA-216 Grades WCB and WCC for thicknesses not exceeding 2 in. (50 mm), if produced to fine grain practice and water-quenched and
tempered
SA-217 Grade WC9 if normalized and tempered
SA-285 Grades A and B
SA-414 Grade A
SA-515 Grade 60
SA-516 Grades 65 and 70 if not normalized
SA-612 if not normalized
SA-662 Grade B if not normalized
SA/EN 10028-2 Grades P295GH and P355GH as-rolled;
(b) except for cast steels, all materials of Curve A if produced to fine grain practice and normalized which are not listed in Curves C and D below;
(c) all pipe, fittings, forgings and tubing not listed for Curves C and D below;
(d) parts permitted under UG-11 shall be included in Curve B even when fabricated from plate that otherwise would be assigned to a
different curve.
(3) Curve C applies to:
(a) SA-182 Grades F21 and F22 if normalized and tempered
SA-302 Grades C and D
SA-336 F21 and F22 if normalized and tempered, or liquid quenched and tempered
SA-387 Grades 21 and 22 if normalized and tempered, or liquid quenched and tempered
SA-516 Grades 55 and 60 if not normalized
SA-533 Grades B and C
SA-662 Grade A;
(b) all materials listed in 2(a) and 2(c) for Curve B if produced to fine grain practice and normalized, normalized and tempered, or liquid
quenched and tempered as permitted in the material specification, and not listed for Curve D below.
(4) Curve D applies to:
SA-203
SA-508 Grade 1
SA-516 if normalized or quenched and tempered
SA-524 Classes 1 and 2
SA-537 Classes 1, 2, and 3
SA-612 if normalized
SA-662 if normalized
SA-738 Grade A
SA-738 Grade A with Cb and V deliberately added in accordance with the provisions of the material specification, not colder than
−20°F (−29°C)
SA-738 Grade B not colder than −20°F (−29°C)
SA/AS 1548 Grades 7-430, 7-460, and 7-490 if normalized
SA/EN 10028-2 Grades P295GH and P355GH if normalized
SA/EN 10028-3 Grade P275NH
181
(10)
2010 SECTION VIII — DIVISION 1
FIG. UCS-66M IMPACT TEST EXEMPTION CURVES
70
60
50
40
A [Note (1)]
Minimum Design Metal Temperature, ºC
30
B [Note (2)]
20
C [Note (3)]
10
0
D [Note (4)]
-10
-20
-30
-40
-48
-50
Impact testing required
-60
10
20
40
60
80
100
Nominal Thickness, mm
[Limited to 100 mm for Welded Construction]
GENERAL NOTE: See Fig. UCS-66 for general notes and notes.
182
120
140
2010 SECTION VIII — DIVISION 1
A of Fig. UCS-66 in thicknesses not exceeding 1⁄4 in.(6
mm) when the minimum design metal temperature is −20°F
(−29°C) or warmer.
(i) For components made of Part UCS materials that
are impact tested, Fig. UCS-66.1 provides a basis for the
use of these components at an MDMT colder than the
impact test temperature.
(1) For such components, the MDMT shall not be
colder than the impact test temperature less the allowable
temperature reduction as determined from Fig. UCS-66.2.
(2) Figure UCS-66.1 may also be used for components not stressed in general primary membrane tensile
stress, such as flat heads, covers, tubesheets, and flanges
(including bolts and nuts). The MDMT shall not be colder
than the impact test temperature less the allowable temperature reduction as determined from Fig. UCS-66.2. The ratio
used in Step 3 of Fig. UCS-66.2 shall be the ratio of
maximum design pressure at the MDMT to the maximum
allowable pressure (MAP) of the component at the MDMT.
(3) In lieu of using (i)(2) above, the MDMT for a
flange attached by welding shall not be colder than the
impact test temperature less the allowable temperature
reduction as determined in (i)(1) above for the neck or
shell to which the flange is attached.
(4) The MDMT adjustment as determined in (i)(1)
above may be used for impact tested welding procedures
or production welds.
(5) The MDMT for the component shall not be colder
than −155°F (−105°C).
(j) When the base metal is exempt from impact testing
by (g) above or by Fig. UCS-66 Curves C or D, −20°F
(−29°C) is the coldest MDMT to be assigned for welded
components that do not meet the requirements of
UCS-67(a)(2).
(c) No impact testing is required for the following
flanges when used at minimum design metal temperatures
no colder than −20°F (−29°C):
(1) ASME B16.5 flanges of ferritic steel;
(2) ASME B16.47 flanges of ferritic steel;
(3) split loose flanges of SA-216 GR WCB when the
outside diameter and bolting dimensions are either ASME
B16.5 Class 150 or Class 300, and the flange thicknesses
are not greater than that of either ASME B16.5 Class 150
or Class 300, respectively.
(4) Carbon and Low Alloy Steel Long Weld Neck
Flanges. Long weld neck flanges are defined as forged
nozzles that meet the dimensional requirements of a flanged
fitting given in ASME B16.5 but having a straight hub/
neck. The neck inside diameter shall not be less than the
nominal size of the flange and the outside diameter of the
neck and any nozzle reinforcement shall not exceed the
diameter of the hub as specified in ASME B16.5.
(d) No impact testing is required for UCS materials 0.10
in. (2.5 mm) in thickness and thinner, but such exempted
UCS materials shall not be used at design metal temperatures colder than −55°F (−48°C). For vessels or components
made from NPS 4 (DN 100) or smaller tubes or pipe of
P-No. 1 materials, the following exemptions from impact
testing are also permitted as a function of the material
specified minimum yield strength (SMYS) for metal temperatures of −155°F (−105°C) and warmer:
SMYS, ksi (MPa)
20 to 35 (140 to 240)
36 to 45 (250 to 310)
46 (320) and higher
Thickness, in. (mm)
0.237 (6.0)
0.125 (3.2)
0.10 (2.5)
(e) The material manufacturer’s identification marking
required by the material specification shall not be stamped
on plate material less than 1⁄4 in. (6 mm) in thickness unless
the following requirements are met.
(1) The materials shall be limited to P-No. 1 Gr. Nos.
1 and 2.
(2) The minimum nominal plate thickness shall be
3
⁄16 in. (5 mm), or the minimum nominal pipe wall thickness
shall be 0.154 in. (3.91 mm).
(3) The minimum design metal temperature shall be
no colder than −20°F (−29°C).
(f) Unless specifically exempted in Fig. UCS-66, materials having a specified minimum yield strength greater than
65 ksi (450 MPa) must be impact tested.
(g) Materials produced and impact tested in accordance
with the requirements of the specifications listed in Fig.
UG-84.1, General Note (c), are exempt from impact testing
by the rules of this Division at minimum design metal
temperatures not more than 5°F (3°C) colder than the test
temperature required by the specification.
(h) No impact testing is required for metal backing strips
which remain in place made of materials assigned to Curve
UCS-67
IMPACT TESTS OF WELDING
PROCEDURES
Except as exempted in UG-20(f), the Welding Procedure
Qualification shall include impact tests of welds and heat
affected zones (HAZ) made in accordance with UG-84
when required by the following provisions. The MDMT
used below shall be the MDMT stamped on the nameplate
or the exemption temperature of the welded component
before applying the temperature reduction permitted by
UCS-66(b) or UCS-68(c).
UCS-67(a) Welds made with filler metal shall be impact
tested in accordance with UG-84 when any of the following
apply:
UCS-67(a)(1) when either base metal is required to
be impact tested by the rules of this Division; or
UCS-67(a)(2) when joining base metals exempt from
impact testing by UCS-66(g) or Fig. UCS-66 Curve C or
D and the minimum design metal temperature is colder
183
2010 SECTION VIII — DIVISION 1
TABLE UCS-66
TABULAR VALUES FOR FIG. UCS-66 AND FIG. UCS-66M
Customary Units
SI Units
Thickness,
in.
Curve
A, °F
Curve
B, °F
Curve
C, °F
Curve
D, °F
0.25
0.3125
0.375
0.4375
0.5
18
18
18
25
32
−20
−20
−20
−13
−7
−55
−55
−55
−40
−34
−55
−55
−55
−55
−55
0.5625
0.625
0.6875
0.75
0.8125
37
43
48
53
57
−1
5
10
15
19
−26
−22
−18
−15
−12
0.875
0.9375
1.0
1.0625
1.125
61
65
68
72
75
23
27
31
34
37
1.1875
1.25
1.3125
1.375
1.4375
77
80
82
84
86
1.5
1.5625
1.625
1.6875
1.75
Thickness,
mm
Curve
A, °C
Curve
B, °C
Curve
C, °C
Curve
D, °C
6.4
7.9
9.5
11.1
12.7
−8
−8
−8
−4
0
−29
−29
−29
−25
−22
−48
−48
−48
−40
−37
−48
−48
−48
−48
−48
−51
−48
−45
−42
−38
14.3
15.9
17.5
19.1
20.6
3
6
9
12
14
−18
−15
−12
−9
−7
−32
−30
−28
−26
−24
−46
−44
−43
−41
−39
−9
−6
−3
−1
2
−36
−33
−30
−28
−26
22.2
23.8
25.4
27.0
28.6
16
18
20
22
24
−5
−3
−1
1
3
−23
−21
−19
−18
−17
−38
−36
−35
−33
−32
40
43
45
47
49
2
6
8
10
12
−23
−21
−19
−18
−16
30.2
31.8
33.3
34.9
36.5
25
27
28
29
30
4
6
7
8
9
−17
−14
−13
−12
−11
−31
−30
−28
−28
−27
88
90
92
93
94
51
53
55
57
58
14
16
17
19
20
−14
−13
−11
−10
−8
38.1
39.7
41.3
42.9
44.5
31
32
33
34
34
11
12
13
14
14
−10
−9
−8
−7
−7
−26
−25
−24
−23
−22
1.8125
1.875
1.9375
2.0
2.0625
96
97
98
99
100
59
61
62
63
64
22
23
24
26
27
−7
−6
−5
−4
−3
46.0
47.6
49.2
50.8
52.4
36
36
37
37
38
15
16
17
17
18
−6
−5
−4
−3
−3
−22
−21
−21
−20
−19
2.125
2.1875
2.25
2.3125
2.375
101
102
102
103
104
65
66
67
68
69
28
29
30
31
32
−2
−1
0
1
2
54.0
55.6
57.2
58.7
60.3
38
39
39
39
40
18
19
19
20
21
−2
−2
−1
−1
0
−19
−18
−18
−17
−17
2.4375
2.5
2.5625
2.625
2.6875
105
105
106
107
107
70
71
71
73
73
33
34
35
36
37
3
4
5
6
7
61.9
63.5
65.1
66.7
68.3
41
41
41
42
42
21
22
22
23
23
1
1
2
2
3
−16
−16
−15
−14
−14
2.75
2.8125
2.875
2.9375
3.0
108
108
109
109
110
74
75
76
77
77
38
39
40
40
41
8
8
9
10
11
69.9
71.4
73.0
74.6
76.2
42
42
43
43
43
23
24
24
25
26
3
4
4
5
5
−13
−13
−13
−12
−12
184
2010 SECTION VIII — DIVISION 1
TABLE UCS-66
TABULAR VALUES FOR FIG. UCS-66 AND FIG. UCS-66M (CONT’D)
Customary Units
Curve
B, °F
SI Units
Thickness,
in.
Curve
A, °F
Curve
C, °F
Curve
D, °F
Thickness,
mm
3.0625
3.125
3.1875
3.25
3.3125
111
111
112
112
113
78
79
80
80
81
42
43
44
44
45
12
12
13
14
15
77.8
79.4
81.0
82.6
84.1
44
44
44
44
45
26
26
27
27
27
6
6
7
7
7
−11
−11
−11
−10
−9
3.375
3.4375
3.5
3.5625
3.625
113
114
114
114
115
82
83
83
84
85
46
46
47
48
49
15
16
17
17
18
85.7
87.3
88.9
90.5
92.1
45
46
46
46
46
28
28
28
29
29
8
8
8
9
9
−9
−9
−8
−8
−7
3.6875
3.75
3.8125
3.875
3.9375
4.0
115
116
116
116
117
117
85
86
87
88
88
89
49
50
51
51
52
52
19
20
21
21
22
23
93.7
95.3
96.8
98.4
100.0
101.6
46
47
47
47
47
47
29
30
31
31
32
32
9
10
11
11
11
11
−7
−7
−6
−6
−6
−5
4.0625
4.125
4.1875
4.25
4.3125
4.375
4.4375
4.5
117
118
118
118
118
119
119
119
90
90
91
91
92
93
93
94
53
54
54
55
55
56
56
57
23
24
25
25
26
27
27
28
103.0
105.0
106.0
108.0
110.0
111.0
113.0
114.0
47
48
48
48
48
49
49
49
32
32
33
33
33
34
34
34
12
12
12
12
12
13
13
13
−5
−4
−4
−4
−3
−3
−3
−2
4.5625
4.625
4.6875
4.75
4.8125
4.875
4.9375
5
119
119
119
119
119
119
119
119
94
95
95
96
96
97
97
97
57
58
58
59
59
60
60
60
29
29
30
30
31
31
32
32
115.0
117.0
118.0
119.0
120.0
121.0
122.0
123.0
49
49
49
49
49
49
49
49
34
35
35
35
35
36
36
36
13
14
14
14
14
15
15
15
−2
−2
−1
−1
−1
−1
0
0
5.0625
5.125
5.1875
5.25
5.3125
5.375
5.4375
5.5
119
119
119
119
119
119
119
119
98
98
98
99
99
100
100
100
61
61
62
62
62
63
63
63
33
33
34
34
35
35
36
36
124.0
125.0
126.0
127.0
128.0
129.0
130.0
131.0
49
49
49
49
49
49
49
49
36
36
36
37
37
37
37
37
15
15
16
16
16
16
16
16
0
0
1
1
1
1
2
2
5.5625
5.625
5.6875
5.75
5.8125
5.875
5.9375
6.0
119
119
119
120
120
120
120
120
101
101
102
102
103
103
104
104
64
64
64
65
65
66
66
66
36
37
37
38
38
38
39
39
132.0
133.0
134.0
135.0
136.0
137.0
138.0
139.0
49
49
49
50
50
50
50
50
38
38
38
38
39
39
39
39
17
17
17
17
17
18
18
18
2
2
2
3
3
3
3
3
185
Curve
A, °C
Curve
B, °C
Curve
C, °C
Curve
D, °C
2010 SECTION VIII — DIVISION 1
FIG. UCS-66.1 REDUCTION IN MINIMUM DESIGN METAL TEMPERATURE WITHOUT IMPACT TESTING
1.00
Ratio: trE*/(tn - c); See Nomenclature for Alternative Ratio
0.90
0.80
0.70
0.60
0.50
0.40
0.35
0.30
0.20
See UCS-66(b)(3) when ratios are 0.35 and smaller
0.10
0.00
0
20
40
60
80
100
120
140
ºF [See UCS-66(b)]
c
E*
tn
tr
corrosion allowance, in.
as defined in General Note (c) of Fig. UCS-66.2
nominal thickness of the component under consideration before corrosion allowance is deducted, in.
required thickness of the component under consideration in the corroded condition for all applicable loadings [General
Note (b) of Fig. UCS-66.2], based on the applicable joint efficiency E [General Note (c) of Fig. UCS-66.2], in.
Alternative Ratio p S*E* divided by the product of the maximum allowable stress value from Table UCS-23 times E, where S* is the applied
general primary membrane tensile stress and E and E* are as defined in General Note (c) of Fig. UCS-66.2
p
p
p
p
186
2010 SECTION VIII — DIVISION 1
FIG. UCS-66.1M REDUCTION IN MINIMUM DESIGN METAL TEMPERATURE WITHOUT IMPACT TESTING
1.00
Ratio: trE*/(tn - c); See Nomenclature for Alternative Ratio
0.90
0.80
0.70
0.60
0.50
0.40
0.35
0.30
0.20
See UCS-66(b)(3) when ratios are 0.35 and smaller
0.10
0.00
0
10
20
30
40
50
60
70
80
ºC [See UCS-66(b)]
c
E*
tn
tr
corrosion allowance, mm
as defined in General Note (c) of Fig. UCS-66.2
nominal thickness of the component under consideration before corrosion allowance is deducted, mm
required thickness of the component under consideration in the corroded condition for all applicable loadings [General
Note (b) of Fig. UCS-66.2], based on the applicable joint efficiency E [General Note (c) of Fig. UCS-66.2], mm
Alternative Ratio p S*E* divided by the product of the maximum allowable stress value from Table UCS-23 times E, where S* is the applied
general primary membrane tensile stress and E and E* are as defined in General Note (c) of Fig. UCS-66.2
p
p
p
p
187
2010 SECTION VIII — DIVISION 1
FIG. UCS-66.2 DIAGRAM OF UCS-66 RULES FOR DETERMINING LOWEST MINIMUM DESIGN METAL
TEMPERATURE (MDMT) WITHOUT IMPACT TESTING
Establish nominal thickness [Note (1)] of welded parts, nonwelded parts, and attachments
under consideration both before and after corrosion allowance is deducted (tn and tn – c, respectively), and
other pertinent data applicable to the nominal thickness such as:
Step 1
All applicable loadings [Note (2)] and coincident minimum design metal
temperature (MDMT)
Materials of construction
E = joint efficiency [Note (3)]
tn = nominal noncorroded thickness [Note (1)], in. (mm)
tr = required thickness in corroded condition for all applicable loadings [Note (2)],
based on the applicable joint efficiency [Note (3)], in. (mm)
Applicable curve(s) of Fig. UCS-66
c = corrosion allowance, in. (mm)
Select MDMT from Fig. UCS-66 [Note (4)] for each
nominal noncorroded governing thickness [Note (5)].
Step 2
Determine Ratio:
Step 3
trE
tn – c
[Notes (3), (6), (7), and (8)]
Step 4
Using Ratio from Step 3 to enter ordinate
of Fig. UCS-66.1, determine reduction in Step
2 MDMT [Note (9)].
Step 5
Determine adjusted MDMT for governing
thickness under consideration.
Repeat for all governing thicknesses [Note (5)] and
take warmest value as the lowest allowable MDMT to be
marked on nameplate for the zone under consideration
[Note (10)]. See UG-116.
See UG-99(h) for coldest recommended metal temperature
during hydrostatic test [Note (6)].
See UG-100(c) for coldest metal temperature permitted
during pneumatic test [Note (6)].
Step 6
Legend
Requirement
Optional
188
2010 SECTION VIII — DIVISION 1
FIG. UCS-66.2 DIAGRAM OF UCS-66 RULES FOR DETERMINING LOWEST MINIMUM DESIGN METAL
TEMPERATURE (MDMT) WITHOUT IMPACT TESTING (CONT’D)
NOTES:
(1) For pipe where a mill undertolerance is allowed by the material specification, the thickness after mill undertolerance has been deducted shall
be taken as the noncorroded nominal thickness tn for determination of the MDMT to be stamped on the nameplate. Likewise, for formed
heads, the minimum specified thickness after forming shall be used as tn .
(2) Loadings, including those listed in UG-22, which result in general primary membrane tensile stress at the coincident MDMT.
(3) E is the joint efficiency (Table UW-12) used in the calculation of tr ; E* has a value equal to E except that E* shall not be less than 0.80.
For castings, use quality factor or joint efficiency E whichever governs design.
(4) The construction of Fig. UCS-66 is such that the MDMT so selected is considered to occur coincidentally with an applied general primary
membrane tensile stress at the maximum allowable stress value in tension from Table 1A of Section II Part D, Tabular values for Fig. UCS66 are shown in Table UCS-66.
(5) See UCS-66(a)(1), (2), and (3) for definitions of governing thickness.
(6) If the basis for calculated test pressure is greater than the design pressure [UG-99(c) test], a Ratio based on the tr determined from the
basis for calculated test pressure and associated appropriate value of tn − c shall be used to determine the recommended coldest metal
temperature during hydrostatic test and the coldest metal temperature permitted during the pneumatic test. See UG-99(h) and UG-100(c).
(7) Alternatively, a Ratio of S*E* divided by the product of the maximum allowable stress value in tension from Table 1A of Section II Part
D times E may be used, where S* is the applied general primary membrane tensile stress and E and E* are as defined in Note (3).
(8) For UCS-66(b)(1)(b) and (i)(2), a ratio of the maximum design pressure at the MDMT to the maximum allowable pressure (MAP) at the
MDMT shall be used. The MAP is defined as the highest permissible pressure as determined by the design formulas for a component using
the nominal thickness less corrosion allowance and the maximum allowable stress value from the Table 1A of Section II, Part D at the
MDMT. For ferritic steel flanges defined in UCS-66(c), the flange rating at the warmer of the MDMT or 100°F (38°C) may be used as the MAP.
(9) For reductions in MDMT up to and including 40°F (22°C), the reduction can be determined by: reduction in MDMT p (1 − Ratio) 100°F
(56°C).
(10) A colder MDMT may be obtained by selective use of impact tested materials as appropriate to the need (see UG-84). See also UCS-68(c).
than −20°F (−29°C) but not colder than −55°F (−48°C),
unless welding consumables which have been classified
by impact tests at a temperature not warmer than the
MDMT by the applicable SFA specification are used; or
UCS-67(a)(3) when joining base metals exempt from
impact testing by UCS-66(g) when the minimum design
metal temperature is colder than −55°F (−48°C).
UCS-67(b) Welds in UCS materials made without the
use of filler metal shall be impact tested when the thickness
at the weld exceeds 1⁄2 in. (13 mm) for all minimum design
metal temperatures or when the thickness at the weld
exceeds 5⁄16 in. (8 mm) and the minimum design metal
temperature is colder than 50°F (10°C). This requirement
does not apply to welds made as part of the material specification.
UCS-67(c) Weld heat affected zones produced with or
without the addition of filler metal shall be impact tested
whenever any of the following apply:
UCS-67(c)(1) when the base metal is required to be
impact tested by the rules of this Division; or
UCS-67(c)(2) when the welds have any individual
weld pass exceeding 1⁄2 in. (13 mm) in thickness, and the
minimum design metal temperature is colder than 70°F
(21°C); or
UCS-67(c)(3) when joining base metals exempt from
impact testing by UCS-66(g) when the minimum design
metal temperature is colder than −55°F (−48°C).
UCS-67(d) Vessel (production) impact tests in accordance with UG-84(i) may be waived for any of the following:
UCS-67(d)(1) weld metals joining steels exempted
from impact testing by UCS-66 for minimum design metal
temperatures of −20°F (−29°C) and warmer; or
UCS-67(d)(2) weld metals defined in (a)(2) above; or
UCS-67(d)(3) heat affected zones (HAZ) in steels
exempted from impact testing by UCS-66, except when
(c)(3) above applies.
UCS-68
DESIGN4
UCS-68(a) Welded joints shall comply with UW-2(b)
when the minimum design metal temperature is colder than
−55°F (−48°C), unless the coincident ratio defined in Fig.
UCS-66.1 is less than 0.35.
UCS-68(b) Welded joints shall be postweld heat treated
in accordance with the requirements of UW-40 when
required by other rules of this Division. When the minimum
design metal temperature is colder than −55°F (−48°C),
and the coincident ratio defined in Fig. UCS-66.1 is 0.35
or greater, postweld heat treatment is required, except that
this requirement does not apply to the following welded
joints, in vessels or vessel parts fabricated of P-No. 1
materials that are impact tested at the MDMT or colder in
accordance with UG-84. The minimum average energy
requirement for base metals and weldments shall be 25 ftlb (34 J) instead of the values shown in Fig. UG-84.1:
4
No provisions of this paragraph waive other requirements of this
Division, such as UW-2(a), UW-2(d), UW-10, and UCS-56.
189
2010 SECTION VIII — DIVISION 1
FIG. UCS-66.3 SOME TYPICAL VESSEL DETAILS SHOWING THE GOVERNING THICKNESSES
AS DEFINED IN UCS-66
GENERAL NOTE: Using tg1, tg2, and tg3, determine the warmest MDMT and use that as the permissible MDMT for the welded assembly.
190
2010 SECTION VIII — DIVISION 1
FIG. UCS-66.3 SOME TYPICAL VESSEL DETAILS SHOWING THE GOVERNING THICKNESSES
AS DEFINED IN UCS-66 (CONT’D)
191
2010 SECTION VIII — DIVISION 1
FIG. UCS-66.3 SOME TYPICAL VESSEL DETAILS SHOWING THE GOVERNING THICKNESSES
AS DEFINED IN UCS-66 (CONT’D)
tB
1
1
tB
B
1
B
A
A
tA
Pressure part
tA
Pressure part
tg1 thinner of tA or tB
(f) Welded Attachments as Defined in UCS-66(a)
C
A
tA
1
tC
tg1 thinner of tA or tC
(g) Integrally Reinforced Welded Connection
GENERAL NOTE: tg p governing thickness of the welded joint as defined in UCS-66.
192
2010 SECTION VIII — DIVISION 1
(1) Type 1 Category A and B joints, not including
cone-to-cylinder junctions, which have been 100% radiographed. Category A and B joints attaching sections of
unequal thickness shall have a transition with a slope not
exceeding 3:1;
(2) fillet welds having leg dimensions not exceeding
3
⁄8 in. (10 mm) attaching lightly loaded attachments, provided the attachment material and the attachment weld
meet requirements of UCS-66 and UCS-67. “Lightly
loaded attachment,” for this application, is defined as an
attachment for which the stress in the attachment weld
does not exceed 25% of the allowable stress. All such
welds shall be examined by magnetic particle or liquid
penetrant examination in accordance with Appendix 6 or
Appendix 8.
UCS-68(c) If postweld heat treating is performed when
it is not otherwise a requirement of this Division, a 30°F
(17°C) reduction in impact testing exemption temperature
may be given to the minimum permissible temperature
from Fig. UCS-66 for P-No. 1 materials. The resulting
exemption temperature may be colder than −55°F (−48°C).
UCS-68(d) The allowable stress values to be used in
design at the minimum design metal temperature shall not
exceed those given in Section II, Part D, Tables 3 for
bolting and 1A for other materials for temperatures of
100°F (38°C).
(see UCS-56) when the resulting extreme fiber elongation
is more than 5% from the as-rolled condition. For P-No.
1 Group Nos. 1 and 2 materials the extreme fiber elongation
may be as great as 40% when none of the following conditions exist:
(1) The vessel will contain lethal substances either
liquid or gaseous (see UW-2).
(2) The material is not exempt from impact testing
by the rules of this Division or impact testing is required
by the material specification.
(3) The thickness of the part before cold forming
exceeds 5⁄8 in. (16 mm).
(4) The reduction by cold forming from the as-rolled
thickness is more than 10% at any location where the
extreme fiber elongation exceeds 5%.
(5) The temperature of the material during forming
is in the range of 250°F to 900°F (120°C to 480°C).
The extreme fiber elongation shall be determined by the
following formulas:
For double curvature (for example, heads),
% extreme fiber elongation p
FABRICATION
冢
50t
R
1− f
Rf
Ro
冣
where
GENERAL
Rf p final centerline radius, in. (mm)
Ro p original centerline radius (equals infinity for flat
plate), in. (mm)
t p plate thickness, in. (mm)
The rules in the following paragraphs apply specifically
to the fabrication of pressure vessels and vessel parts that
are constructed of carbon and low alloy steel and shall
be used in conjunction with the general requirements for
Fabrication in Subsection A, and with the specific requirements for Fabrication in Subsection B that pertain to the
method of fabrication used.
UCS-79
冣
For single curvature (for example, cylinders),
% extreme fiber elongation p
UCS-75
冢
75t
R
1− f
Rf
Ro
UCS-85
HEAT TREATMENT OF TEST
SPECIMENS
UCS-85(a) The following provisions shall apply in
addition to, or as exceptions to the general rules for heat
treatment given in UG-85.
UCS-85(b) Heat treatment as used in this section shall
include all thermal treatments of the material during fabrication exceeding 900°F (480°C), except as exempted
below.
UCS-85(c) The material used in the vessel shall be represented by test specimens which have been subjected to
the same heat treatments above the lower transformation
temperature and postweld heat treatment except as provided in (e), (f), (g), (h), and (i) below. The kind and
number of tests and test results shall be as required by
the material specification. The vessel Manufacturer shall
specify the temperature, time, and cooling rates to which
FORMING SHELL SECTIONS AND
HEADS
(a) The following provisions shall apply in addition to
the general rules for forming given in UG-79.
(b) Carbon and low alloy steel plates shall not be formed
cold by blows.
(c) Carbon and low alloy steel plates may be formed
by blows at a forging temperature provided the blows do
not objectionably deform the plate and it is subsequently
postweld heat treated.
(d) Vessel shell sections, heads, and other pressure
boundary parts of carbon and low alloy steel plates fabricated by cold forming shall be heat treated subsequently
193
2010 SECTION VIII — DIVISION 1
the material will be subjected during fabrication, except
as permitted in (h) below. Material from which the specimens are prepared shall be heated at the specified temperature within reasonable tolerances such as are normal in
actual fabrication. The total time at temperature shall be
at least 80% of the total time at temperature during actual
heat treatment of the product and may be performed in a
single cycle.
UCS-85(d) Thermal treatment of material is not
intended to include such local heating as thermal cutting,
preheating, welding, or heating below the lower transformation temperature of tubing and pipe for bending or
sizing.
UCS-85(e) An exception to the requirements of (c)
above and UG-85 shall apply to standard items such as
described in UG-11(a). These may be subject to postweld
heat treatment with the vessel or vessel part without the
same treatment being required of the test specimens. This
exception shall not apply to specially designed cast or
wrought fittings.
UCS-85(f) Materials conforming to one of the specifications listed in P-No. 1 Group Nos. 1 and 2 of QW-422
and all carbon and low alloy steels used in the annealed
condition as permitted by the material specification are
exempt from the requirements of (c) above when the heat
treatment during fabrication is limited to postweld heat
treatment at temperatures below the lower transformation
temperature of the steel.
UCS-85(g) Materials listed in QW-422 as P-No. 1
Group No. 3 and P-No. 3 Group Nos. 1 and 2 that are
certified in accordance with (c) above from test specimens
subjected to the PWHT requirements of Table UCS-56
need not be recertified if subjected to the alternate PWHT
conditions permitted by Table UCS-56.1.
UCS-85(h) The simulation of cooling rates for test specimens from nonimpact tested materials 3 in. and under in
thickness is not required for heat treatments below the
lower transformation temperature.
UCS-85(i) All thermal treatments which precede a thermal treatment that fully austenitizes the material need not
be accounted for by the specimen heat treatments, provided
the austenitizing temperature is at least as high as any of
the preceding thermal treatments.
MARKING AND REPORTS
UCS-115
The provisions for marking and reports in UG-115
through UG-120 shall apply without supplement to pressure vessels constructed of carbon and low alloy steels.
PRESSURE RELIEF DEVICES
UCS-125
GENERAL
The provisions for pressure relief devices in UG-125
through UG-136 shall apply without supplement to pressure vessels constructed of carbon and low alloy steels.
NONMANDATORY APPENDIX CS
UCS-150
GENERAL
See Appendix A, A-100, of Section II, Part D.
UCS-151
CREEP-RUPTURE PROPERTIES OF
CARBON STEELS
See Appendix A, A-200, of Section II, Part D.
UCS-160
VESSELS OPERATING AT
TEMPERATURES COLDER THAN
THE MDMT STAMPED ON THE
NAMEPLATE
(a) Vessels or components may be operated at temperatures colder than the MDMT stamped on the nameplate,
provided the provisions of UCS-66, UCS-67 and UCS-68
are met when using the reduced (colder) operating temperature as the MDMT, but in no case shall the operating
temperature be colder than −155°F (−105°C).
(b) As an alternative to (a) above, for vessels or components whose thicknesses are based on pressure loading
only, the coincident operating temperature may be as cold
as the MDMT stamped on the nameplate less the allowable
temperature reduction as determined from Fig. UCS-66.2.
The ratio used in Step 3 of Fig. UCS-66.2 shall be the
ratio of maximum pressure at the coincident operating
temperature to the MAWP of the vessel at the stamped
MDMT, but in no case shall the operating temperature be
colder than −155°F (−105°C).
INSPECTION AND TESTS
UCS-90
GENERAL
GENERAL
The provisions for inspection and testing in Subsections
A and B shall apply without supplement to vessels constructed of carbon and low alloy steels.
194
2010 SECTION VIII — DIVISION 1
PART UNF
REQUIREMENTS FOR PRESSURE VESSELS
CONSTRUCTED OF NONFERROUS MATERIALS
in Section II and shall be limited to those listed in Tables
UNF-23.1 through UNF-23.5 except as otherwise provided
in UG-10 and UG-11.
(b) Appendix NF of this Division of Section VIII and
the paragraph entitled Basis of Purchase and the appendix
of the applicable material specification contain information
relative to the fabricating characteristics of the material.
They are intended to help the manufacturer in ordering
the correct material, and in fabricating it, and to help the
producer to select the material best able to fulfill the
requirements of the fabricating procedures to be used.
GENERAL
UNF-1
SCOPE
The rules in Part UNF are applicable to pressure vessels
and vessel parts that are constructed of nonferrous materials
and shall be used in conjunction with the general requirements in Subsection A, and with the specific requirements
in Subsection B that pertain to the method of fabrication
used.
UNF-3
USES
Some of the uses of nonferrous materials are to resist
corrosion, to facilitate cleaning of vessels for processing
foods, to provide strength or scaling-resistance at high
temperatures, and to provide notch toughness at low temperatures.
UNF-4
UNF-6
Approved specifications for nonferrous plates are given
in Tables UNF-23.1 through UNF-23.5. A tabulation of
allowable stress values at different temperatures is given
in Table 1B of Section II, Part D (see UG-5).
CONDITIONS OF SERVICE
UNF-7
Specific chemical compositions, heat-treatment procedures, fabrication requirements, and supplementary tests
may be required to assure that the vessel will be in its
most favorable condition for the intended service. This is
particularly true for vessels subject to severe corrosion.
These rules do not indicate the selection of nonferrous
material suitable for the intended service or the amount of
the corrosion allowance to be provided. It is recommended
that users assure themselves by appropriate tests, or otherwise, that the nonferrous material selected will be suitable
for the intended service both with respect to corrosion and
to retention of satisfactory mechanical properties during
the desired service life, taking into account any heating or
heat treatment that might be performed during fabrication.
See also Appendix A, A-400, of Section II, Part D.
FORGINGS
Approved specifications for nonferrous forgings are
given in Tables UNF-23.1 through UNF-23.5. A tabulation
of allowable stress values at different temperatures is given
in Table 1B of Section II, Part D (see UG-6).
UNF-8
CASTINGS
Approved specifications for nonferrous castings are
given in Tables UNF-23.1 through UNF-23.5. A tabulation
of allowable stress values at different temperatures is given
in Table 1B of Section II, Part D. These stress values are
to be multiplied by the casting quality factors of UG-24.
Castings that are to be welded shall be of a weldable grade.
UNF-12
MATERIALS
UNF-5
NONFERROUS PLATE
BOLT MATERIALS
(a) Approved specifications for bolt materials are given
in Tables UNF-23.1 through UNF-23.5. A tabulation of
allowable stress values at different temperatures is given
in Table 3 of Section II, Part D.
GENERAL
(a) All nonferrous materials subject to stress due to
pressure shall conform to one of the specifications given
195
2010 SECTION VIII — DIVISION 1
(b) When bolts are machined from heat treated, hot
rolled, or cold worked material and are not subsequently
hot worked or annealed, the allowable stress values in
Table 3 to be used in design shall be based on the condition
of the material selected.
(c) When bolts are fabricated by hot-heading, the allowable stress values for annealed material in Table 3 shall
apply unless the manufacturer can furnish adequate control
data to show that the tensile properties of hot rolled bars
or hot finished forgings are being met, in which case the
allowable stress values for the material in the hot finished
condition may be used.
(d) When bolts are fabricated by cold heading, the
allowable stress values for annealed material in Table 3
shall apply unless the manufacturer can furnish adequate
control data to show that higher design stresses, as agreed
upon, may be used. In no case shall such stresses exceed
the allowable stress values given in Table 3 for cold worked
bar stock.
(e) Ferrous bolts, studs, and nuts may be used provided
they are suitable for the application. They shall conform
to the requirements of UCS-10 and 11.
UNF-13
general requirements for Design in Subsection A, and with
the specific requirements for Design in Subsection B that
pertain to the method of fabrication used.
UNF-19
(a) For vessels constructed of titanium or zirconium and
their alloys, all joints of Categories A and B shall be of
Type No. (1) or No. (2) of Table UW-12.
(b) Titanium or zirconium and their alloys shall not be
welded to other materials.
(c) For vessels constructed of UNS N06625, all joints
of Categories A and B shall be Type No. (1) or No. (2)
of Table UW-12. All joints of Categories C and D shall
be Type No. (1) or No. (2) of Table UW-12 when the
design temperature is 1,000°F (540°C) or higher.
(d) For vessels constructed of UNS N12160, the nominal thickness of the base material at the weld shall not
exceed 0.5 in. (13 mm). When welding is performed with
filler metal of the same nominal composition as the base
metal, only GMAW or GTAW processes are allowed and
the nominal weld deposit thickness shall not exceed 0.5
in. (13 mm).
(e) For vessels constructed of UNS N06230 and UNS
N06210 and when welding is performed with filler metal
of the same nominal composition as the base metal, only
GMAW or GTAW processes are allowed. For applications
using UNS N06230 above 1,650°F (900°C), welding shall
be limited to the GTAW and GMAW welding processes
using SFA-5.14, ERNiCrWMo-1.
(f) For vessels constructed of UNS R31233 during weld
procedure qualification testing, when using a matching
filler metal composition, the minimum specified tensile
strength of the weld metal shall be 120 ksi (828 MPa).
Longitudinal bend tests are permitted per Section IX,
QW-160.
NUTS AND WASHERS
Nuts and washers may be made from any suitable material listed in Tables UNF-23.1 through UNF-23.5. Nuts
may be of any dimension or shape provided their strength
is equal to that of the bolting, giving due consideration to
bolt hole clearance, bearing area, thread form and class of
fit, thread shear, and radial thrust from threads [see U-2(g)].
UNF-14
RODS, BARS, AND SHAPES
Rods, bars and shapes shall conform to one of the specifications in Tables UNF-23.1 through UNF-23.5.
UNF-15
OTHER MATERIALS
(a) Other materials, either ferrous or nonferrous, may
be used for parts of vessels provided that they are suitable
for the purpose intended.
(b) The user shall satisfy himself that the coupling of
dissimilar metals will have no harmful effect on the corrosion rate or service life of the vessel for the service
intended.
(c) Other materials used in conjunction with nonferrous
metals shall meet the requirements given for those materials
in other parts of this Division.
UNF-23
MAXIMUM ALLOWABLE STRESS
VALUES
(a) Tables 3 (for bolting) and 1B (other materials) in
Section II, Part D give the maximum allowable stress values at the temperatures indicated for materials conforming
to the specifications listed therein. Values may be interpolated for intermediate temperatures [see UG-23 and
UG-31(a)]. For vessels designed to operate at a temperature
colder than −20°F (−29°C), the allowable stress values to
be used in design shall not exceed those given for temperatures of −20°F to 100°F (−29°C to 38°C).
(b) Shells of pressure vessels may be made from welded
pipe or tubing listed in Tables UNF-23.1, UNF-23.2,
UNF-23.3, UNF-23.4, and UNF-23.5.
(c) When welding or brazing is to be done on material
having increased tensile strength produced by hot or cold
DESIGN
UNF-16
WELDED JOINTS
GENERAL
The rules in the following paragraphs apply specifically
to the design of pressure vessels and vessel parts of nonferrous materials and shall be used in conjunction with the
196
2010 SECTION VIII — DIVISION 1
TABLE UNF-23.1
NONFERROUS METALS — ALUMINUM AND ALUMINUM ALLOY PRODUCTS
Spec.
No.
Spec.
No.
Alloy Designation/UNS No.
SB-26
A02040, A03560, A24430
SB-108
A02040, A03560
SB-209
Alclad 3003, 3004, 6061; A91060, A91100,
A93003, A93004, A95052, A95083, A95086,
A95154, A95254, A95454, A95456, A95652,
A96061
SB-210
Alclad 3003; A91060, A93003, A95052,
A95154, A96061, A96063
SB-211
A92014, A92024, A96061
SB-221
A91060, A91100, A92024, A93003, A95083,
A95086, A95154, A95454, A95456, A96061,
A96063
Alloy Designation/UNS No.
SB-234
Alclad 3003; A91060, A93003, A95052,
A95454, A96061
SB-241
Alclad 3003; A91060, A91100, A93003, A95052,
A95083, A95086, A95454, A95456, A96061,
A96063
SB-247
A92014, A93003, A95083, A96061
SB-308
A96061
SB-928
A95083, A95086, A95456
GENERAL NOTE: Maximum allowable stress values in tension for the materials listed in the above table are contained in Subpart 1 of Section
II, Part D (see UG-23).
TABLE UNF-23.2
NONFERROUS METALS — COPPER AND COPPER ALLOYS
Spec.
No.
Spec.
No.
UNS No.
SB-42
C10200, C12000, C12200
SB-43
C23000
SB-61
C92200
SB-62
C83600
SB-75
C10200, C12000, C12200, C14200
SB-96
C65500
SB-98
C65100, C65500, C66100
SB-111
C10200, C12000, C12200, C14200, C19200,
C23000, C28000, C44300, C44400, C44500,
C60800, C68700, C70400, C70600, C71000,
C71500, C72200
SB-135
C23000
SB-148
C95200, C95400
SB-150
C61400, C62300, C63000, C64200
SB-152
C10200, C10400, C10500, C10700, C11000,
C12200, C12300
SB-169
C61400
UNS No.
SB-171
C36500, C44300, C44400, C44500, C46400,
C46500, C61400, C63000, C70600, C71500
SB-187
C10200, C11000
SB-271
C95200
SB-283
C37700, C64200
SB-315
C65500
SB-359
C12200, C44300, C44400, C44500, C70600,
C71000, C71500
SB-395
C10200, C12000, C12200, C14200, C19200,
C23000, C44300, C44400, C44500, C60800,
C68700, C70600, C71000, C71500
SB-466
C70600, C71000, C71500
SB-467
C70600
SB-543
C12200, C19400, C23000, C44300, C44400,
C44500, C68700, C70400, C70600, C71500
SB-584
C92200, C93700, C97600
SB-956
C70600, C71500
GENERAL NOTE: Maximum allowable stress values in tension for the materials listed in the above table are contained in Subpart 1 of Section
II, Part D (see UG-23).
197
2010 SECTION VIII — DIVISION 1
TABLE UNF-23.3
NONFERROUS METALS — NICKEL, COBALT, AND HIGH NICKEL ALLOYS
Spec.
No.
Spec.
No.
UNS No.
SA-351
J94651
SA-494
N26022, N30002, N30012
SB-127
UNS No.
SB-462
N06022, N06030, N06035, N06045, N06059,
N06200, N06686, N08020, N08031, N08367,
N10276, N10629, N10665, N10675, R20033
N04400
SB-463
N08020, N08024, N08026
SB-160
N02200, N02201
SB-464
N08020, N08024, N08026
SB-161
N02200, N02201
SB-468
N08020, N08024, N08026
SB-162
N02200, N02201
SB-473
N08020
SB-163
N02200, N02201, N04400, N06600, N06601,
N08120, N08801,N08800, N08810, N08811,
N08825
SB-511
N08330
SB-514
N08120, N08800, N08810
SB-164
N04400, N04405
SB-515
N08120, N08800, N08810, N08811
SB-165
N04400
SB-516
N06045, N06600
SB-166
N06045, N06600, N06601, N06617, N06690
SB-517
N06045, N06600
SB-167
N06045, N06600, N06601, N06617, N06690
SB-525
N08330
SB-168
N06045, N06600, N06601, N06617, N06690
SB-536
N08330
SB-333
N10001, N10629, N10665, N10675
SB-564
SB-335
N10001, N10629, N10665, N10675
SB-366
N02200, N02201, N04400, N06002, N06007,
N06022, N06030, N06035, N06045, N06059,
N06200, N06210, N06230, N06455, N06600,
N06625, N06985, N08020, N08031, N08120,
N08330, N08367, N08800, N08825, N10001,
N10003, N10242, N10276, N10629, N10665,
N10675, N12160, R20033
N04400, N06022, N06035, N06045, N06059,
N06200, N06210, N06230, N06600, N06617,
N06625, N06686, N08031, N08120, N08367,
N08800, N08810, N08811, N08825, N10242,
N10276, N10629, N10665, N10675,
N12160, R20033
SB-572
N06002, N06230, N12160, R30556
SB-573
N10003, N10242
SB-574
N06022, N06030, N06035, N06059, N06200,
N06210, N06455, N06686, N10276
SB-575
N06022, N06059, N06035, N06200, N06210,
N06455, N06686, N10276
SB-581
N06007, N06030, N06975, N06985, N08031
SB-582
N06007, N06030, N06975, N06985
SB-599
N08700
SB-619
N06002, N06007, N06022, N06030, N06035,
N06059, N06200, N06230, N06455, N06686,
N06975, N06985, N06210, N08031, N08320,
N10001, N10242, N10276, N10629, N10665,
N10675, R20033, R30556
SB-620
N08320
SB-621
N08320
SB-622
N06002, N06007, N06022, N06030, N06035,
N06059, N06200, N06210, N06230 N06455,
N06686, N06975, N06985, N08031, N08320,
N10001, N10242, N10276, N10629, N10665,
N10675, R20033, R30556
SB-407
N08120, N08801, N08800, N08810, N08811
SB-408
N08120, N08800, N08810, N08811
SB-409
N08120, N08800, N08810, N08811
SB-423
N08825
SB-424
N08825
SB-425
N08825
SB-434
N10003, N10242
SB-435
N06002, N06230, R30556
SB-443
N06625
SB-444
N06625
SB-446
N06625
198
2010 SECTION VIII — DIVISION 1
TABLE UNF-23.3
NONFERROUS METALS — NICKEL, COBALT, AND HIGH NICKEL ALLOYS (CONT’D)
Spec.
No.
Spec.
No.
UNS No.
UNS No.
SB-625
N08031, N08904, N08925, R20033
SB-677
N08904, N08925
SB-626
N06002, N06007, N06022, N06030, N06035,
N06059, N06200, N06210, N06230, N06455,
N06975, N06985, N08031, N08320, N10001,
N10242, N10276, N10629, N10665, N10675,
N12160, R20033, R30556
SB-688
N08367
SB-690
N08367
SB-691
N08367
SB-637
N07718, N07750
SB-704
N06625, N08825
SB-649
N08904, N08925, R20033
SB-705
N06625, N08825
SB-668
N08028
SB-709
N08028
SB-672
N08700
SB-710
N08330
SB-673
N08904, N08925
SB-729
N08020
SB-674
N08904, N08925
SB-804
N08367
SB-675
N08367
SB-815
R31233
SB-676
N08367
SB-818
R31233
SF-468
N05500
SF-467
N05500
SF-467M
N05500
GENERAL NOTE: Maximum allowable stress values in tension for the materials listed in the above table are contained in Subpart 1 of Section
II, Part D (see UG-23).
(10)
TABLE UNF-23.4
NONFERROUS METALS — TITANIUM AND TITANIUM ALLOYS
Spec.
No.
Spec.
No.
UNS No.
UNS No.
SB-265
R50250, R50400, R50550, R52250, R52252, R52254,
R52400, R52402, R52404, R53400, R56320, R56323
SB-381
R50250, R50400, R50550, R52400, R52402,
R52404, R53400, R56323
SB-338
R50250, R50400, R50550, R52400, R52402, R52404,
R53400, R56320, R56323
SB-861
R50250, R50400, R50550, R52400, R52404,
R53400, R56320, R56323
SB-348
R50250, R50400, R50550, R52400, R52402, R52404,
R53400, R56323
SB-862
R50250, R50400, R50550, R52400, R52404,
R53400, R56320, R56323
SB-363
R50250, R50400, R50550, R52400, R52404, R53400,
R56323
GENERAL NOTE: Maximum allowable stress values in tension for the materials listed in the above table are contained in Subpart 1 of Section
II, Part D (see UG-23).
199
2010 SECTION VIII — DIVISION 1
TABLE UNF-23.5
NONFERROUS METALS — ZIRCONIUM
Spec.
No.
UNS No.
Spec.
No.
UNS No.
SB-493
R60702, R60705
SB-551
R60702, R60705
SB-523
R60702, R60705
SB-653
R60702, R60705
SB-550
R60702, R60705
SB-658
R60702, R60705
GENERAL NOTE: Maximum allowable stress values in tension for the materials listed in the above table are contained in Subpart 1 of Section
II, Part D (see UG-23).
working, the allowable stress value for the material in the
annealed condition shall be used for joint design. Onepiece heads and seamless shells may be designed on the
basis of the actual temper of the material.
(d) When welding or brazing is to be done on material
having increased tensile strength produced by heat treatment, the allowable stress value for the material in the
annealed condition shall be used for the joint design unless
the stress values for welded construction are given in Table
1B or 3 in Section II, Part D or unless the finished construction is subjected to the same heat treatment as that which
produced the temper in the “as-received” material, provided the welded joint and the base metal are similarly
affected by the heat treatment.
UNF-28
UNF-56
(a) Postweld heat treatment of nonferrous materials is
not normally necessary nor desirable.
(b) Except as in (c), (d), and (e) below, no postweld
heat treatment shall be performed except by agreement
between the user and the Manufacturer. The temperature,
time and method of heat treatment shall be covered by
agreement.
(c) If welded, castings of SB-148, Alloy CDA 954 shall
be heat treated after all welding at 1150°F–1200°F (620°C–
650°C) for 11⁄2 hr at temperature for the first inch of cross
section thickness plus 1⁄2 hr for each additional inch of
section thickness. Material shall then be air cooled.
(d) Within 14 days after welding, all products of zirconium Grade R60705 shall be heat treated at 1,000°F–
1,100°F (540°C–595°C) for a minimum of 1 hr for thicknesses up to 1 in. (25 mm) plus 1⁄2 hr for each additional
inch of thickness. Above 800°F (425°C), cooling shall be
done in a closed furnace or cooling chamber at a rate not
greater than 500°F /hr (278°C /h) divided by the maximum
metal thickness of the shell or head plate in inches but
in no case more than 500°F /hr (278°C/h). From 800°F
(425°C), the vessel may be cooled in still air.
(e) Postweld Heat Treatment of UNS Nos. N08800,
N08810, and N08811 Alloys
(1) Pressure boundary welds and welds to pressure
boundaries in vessels with design temperatures above
1000°F fabricated from UNS No. N08800 (Alloy 800),
UNS No. N08810 (Alloy 800H), and UNS No. N08811
(Alloy 800HT) shall be postweld heat treated. The postweld
heat treatment shall consist of heating to a minimum temperature of 1,625°F (885°C) for 11⁄2 hr for thicknesses up
to 1 in. (25 mm), and for 11⁄2 hr + 1 hr/in. of thickness for
thicknesses in excess of 1 in. (25 mm). Cooling and heating
rates shall be by agreement between the purchaser and
fabricator. As an alternative, solution annealing in accordance with the material specification is acceptable. Postweld heat treatment of tube-to-tubesheet and expansion
bellows attachment welds is neither required nor prohibited.
THICKNESS OF SHELLS UNDER
EXTERNAL PRESSURE
(a) Cylindrical and spherical shells under external pressure shall be designed by the rules in UG-28, using the
applicable figures in Subpart 3 of Section II, Part D and
the temperature limits of UG-20(c).
(b) Examples illustrating the use of the charts in the
figures for the design of vessels under external pressure
are given in Appendix L.
UNF-30
STIFFENING RINGS
Rules covering the design and attachment of stiffening
rings are given in UG-29 and UG-30.
UNF-33
POSTWELD HEAT TREATMENT
FORMED HEADS, PRESSURE ON
CONVEX SIDE
Ellipsoidal, torispherical, hemispherical, and conical
heads having pressure on the convex side (minus heads)
shall be designed by the rules of UG-33, using fig-ures in
Subpart 3 of Section II, Part D having NFA, NFC, NFN,
NFT, and NFZ designators. Examples illustrating the application of this paragraph are given in Appendix L.
200
2010 SECTION VIII — DIVISION 1
(2) Except as permitted in (3) below, vessels or parts
of vessels that have been postweld heat treated in accordance with the requirements of this paragraph shall again
be postweld heat treated after welded repairs have been
made.
(3) Weld repairs to the weld metal and heat affected
zone in welds joining these materials may be made after
the final PWHT, but prior to the final hydrostatic test,
without additional PWHT. The weld repairs shall meet the
requirements of (e)(3)(a) through (e)(3)(d) below.
(a) The Manufacturer shall give prior notification
of the repair to the user or to his designated agent and
shall not proceed until acceptance has been obtained.
(b) The total repair depth shall not exceed 1⁄2 in.
(13 mm) or 30% of the material thickness, whichever is
less. The total depth of a weld repair shall be taken as the
sum of the depths for repairs made from both sides of a
weld at a given location.
(c) After removal of the defect, the groove shall
be examined. The weld repair area must also be examined.
The liquid penetrant examination method, in accordance
with Appendix 8, shall be used.
(d) The vessel shall be hydrostatically tested after
making the welded repair.
(f) Postweld heat treatment of UNS R31233 is required
prior to cold forming when the cold forming bend radius
at the weld is less than four (4) times the thickness of the
component. Postweld treatment shall consist of annealing
at 2,050°F (1 121°C) immediately followed by water
quenching.
UNF-57
UNF-58
LIQUID PENETRANT EXAMINATION
(a) All welds, both groove and fillet, in vessels constructed of materials covered by UNS N06625 (for Grade
2 only in SB-443, SB-444, and SB-446), UNS N10001,
and UNS N10665 shall be examined for the detection of
cracks by the liquid penetrant method. This examination
shall be made following heat treatment if heat treatment
is performed. All cracks shall be removed by grinding, or
grinding and filing. Where a defect is removed and welding
repair is not necessary, care shall be taken to contour
notches or corners. The contoured surface shall then be
reinspected by the same means originally used for locating
the defect to be sure it has been completely removed.
(b) All joints in vessels constructed of titanium or zirconium and their alloys shall be examined by the liquid
penetrant method of Appendix 8.
(c) Welded joints in vessels or parts of vessels, constructed of materials listed in Table UNF-23.3, with the
exception of alloys 200 (UNS No. N02200), 201 (UNS
No. N02201), 400 (UNS No. N04400), 405 (UNS No.
N04405), and 600 (UNS No. N06600), shall be examined
by the liquid penetrant method when they are not required
to be fully radiographed.
(d) Laser and resistance welded lap joints are exempt
from liquid penetrant examination requirements of (a), (b),
and (c) above.
UNF-65
LOW TEMPERATURE OPERATION
The materials listed in Tables UNF-23.1 through
UNF-23.5, together with deposited weld metal within the
range of composition for material in that Table, do not
undergo a marked drop in impact resistance at subzero
temperature. Therefore, no additional requirements are
specified for wrought aluminum alloys when they are used
at temperatures down to −452°F (−269°C); for copper and
copper alloys, nickel and nickel alloys, and cast aluminum
alloys when they are used at temperatures down to −325°F
(−198°C); and for titanium or zirconium and their alloys
used at temperatures down to −75°F (−59°C). The materials
listed in Tables UNF-23.1 through UNF-23.5 may be used
at lower temperatures than those specified herein and for
other weld metal compositions provided the user satisfies
himself by suitable test results such as determinations of
tensile elongation and sharp-notch tensile strength (compared to unnotched tensile strength) that the material has
suitable ductility at the design temperature.
RADIOGRAPHIC EXAMINATION
(a) Vessels or parts of vessels constructed of nonferrous
materials shall be radiographed in accordance with the
requirements of UW-11.
(b) In addition, for vessels constructed of titanium or
zirconium and their alloys, all joints of Categories A and
B shall be fully radiographed in accordance with UW-51.
(c) Welded butt joints in vessels constructed of materials listed in Table UNF-23.3, with the exception of alloys
200 (UNS No. N02200), 201 (UNS No. N02201), 400
(UNS No. N04400), 401 (UNS No. N04401), and 600
(UNS No. N06600), shall be examined radiographically
for their full length as prescribed in UW-51 when the
thinner of the plate or vessel wall thicknesses at the welded
joint exceeds 3⁄8 in. (10 mm).
(d) Where a defect is removed and welding repair is
not necessary, care shall be taken to contour notches or
corners. The contoured surface shall then be reinspected
by the same means originally used for locating the defect
to be sure it has been completely removed.
FABRICATION
UNF-75
GENERAL
The rules in the following paragraphs apply specifically
to the fabrication of pressure vessels and vessel parts that
201
2010 SECTION VIII — DIVISION 1
TABLE UNF-79
POSTFABRICATION STRAIN LIMITS AND REQUIRED HEAT TREATMENT
(10)
Limitations in Higher
Temperature Range
Limitation in Lower Temperature Range
For Design Temperature,
°F (°C)
Grade
UNS
Number
600
617
800
800H
...
N06600
N06617
N08800
N08810
N08811
Exceeding
1,075
1,000
1,100
1,100
1,100
(580)
(540)
(595)
(595)
(595)
But Less Than or
Equal To
1,200
1,250
1,250
1,250
1,250
(650)
(675)
(675)
(675)
(675)
And Forming
Strains
Exceeding,
%
20
15
15
15
15
For Design
Temperature,
°F (°C),
Exceeding
1,200
1,250
1,250
1,250
1,250
(650)
(675)
(675)
(675)
(675)
And Forming
Strain
Exceeding,
%
Minimum Heat Treatment
Temperature, °F (°C), When
Design Temperature and
Forming Strain Limits are
Exceeded [Note (1)]
10
10
10
10
10
1,900 (1 040)
2,100 (1 150)
1,800 (980)
2,050 (1 120)
2,050 (1 120)
GENERAL NOTES:
(a) The limits shown are for cylinders formed from plates, spherical or dished heads formed from plate, and tube and pipe bends.
(b) When the forming strains cannot be calculated as shown in UNF-79(a), the forming strain limits shall be half those tabulated in this Table
[see UNF-79(b)].
NOTE:
(1) Rate of cooling from heat-treatment temperature is not subject to specific control limits.
are constructed of nonferrous materials and shall be used
in conjunction with the general requirements for Fabrication in Subsection A, and with the specific requirements
for Fabrication in Subsection B that pertain to the method
of fabrication used.
UNF-77
UNF-79
REQUIREMENTS FOR
POSTFABRICATION HEAT
TREATMENT DUE TO STRAINING
UNF-79(a) The following rules shall apply in addition
to general rules for forming given in UNF-77.
UNF-79(a)(1) If the following conditions prevail, the
cold formed areas of pressure-retaining components manufactured of austenitic alloys shall be solution annealed by
heating at the temperatures given in Table UNF-79 for 20
min/in. (20 min/25 mm) of thickness or 10 min, whichever
is greater, followed by rapid cooling:
(a) the finishing-forming temperature is below the
minimum heat-treating temperature given in Table UNF79; and
(b) the design metal temperature and the forming
strains exceed the limits shown in Table UNF-79.
UNF-79(a)(2) Forming strains shall be calculated as
follows:
(a) cylinders formed from plate:
FORMING SHELL SECTIONS AND
HEADS
The following provisions shall apply in addition to the
general rules for forming given in UG-79:
(a) The selected thickness of material shall be such that
the forming processes will not reduce the thickness of the
material at any point below the minimum value required
by the design computation.
(b) Relatively small local bulges and buckles may be
removed from formed parts for shells and heads by hammering or by local heating and hammering. For limiting
temperatures see Appendix NF.
(c) A shell section that has been formed by rolling may
be brought true-to-round for its entire length by pressing,
rolling, or hammering.
% strain p
冢
50t
R
1− f
Rf
Ro
冣
(b) spherical or dished heads formed from plate:
% strain p
UNF-78
(10)
WELDING
冢
75t
R
1− f
Rf
Ro
冣
(c) tube and pipe bends: the larger of
Welding of titanium or zirconium and their alloys is to be
by the gas-shielded tungsten arc process, the gas-shielded
metal arc (consumable-electrode) process, the plasma arc
welding process, the electron beam process, the laser beam
process, or the resistance welding process, meeting the
requirements of Section IX or Appendix 17 of this Division,
whichever is applicable.
% strain p
100r
R
FIG. UNF-79 DELETED
202
(10)
2010 SECTION VIII — DIVISION 1
or
% strain p
冢
plate shall be attached to one end of the longitudinal joint
and welded continuously with the joint. Where circumferential joints only are involved, the test plate need not be
attached but shall be welded along with the joint and each
welder or welding operator shall deposit weld metal in the
test plate at the location and proportional to that deposited
in the production weld. Test plates shall represent each
welding process or combination of processes or a change
from machine to manual or vice versa. At least one test
plate is required for each vessel provided not over 100 ft
of Category A or B joints are involved. An additional test
plate, meeting the same requirements as outlined above,
shall be made for each additional 100 ft of Category A or
B joints involved. The bend specimens shall be prepared
and tested in accordance with Section IX, QW-160. Failure
of either bend specimen constitutes rejection of the weld.
冣
tA − t B
100
tA
where
R p nominal bending radius to center line of pipe or
tube
Rf p mean radius after forming
Ro p original radius (equal to infinity for a flat plate)
r p nominal outside radius of pipe or tube
t p nominal thickness of the plate, pipe, or tube before
forming
tA p measured average wall thickness of pipe or tube
tB p measured minimum wall thickness of the extrados
of the bend
UNF-79(b) When forming strains cannot be calculated
as shown in (a) above, the Manufacturer shall have the
responsibility to determine the maximum forming strain.
For flares, swages, or upsets, heat treatment in accordance
with Table UNF-79 shall apply, regardless of the amount
of strain.
MARKING AND REPORTS
UNF-115
The provisions for marking and reports in UG-115
through UG-120 shall apply without supplement to pressure vessels constructed of nonferrous materials.
INSPECTION AND TESTS
UNF-90
GENERAL
PRESSURE RELIEF DEVICES
The rules in the following paragraphs apply specifically
to the inspection and testing of pressure vessels and vessel
parts that are constructed of nonferrous materials and shall
be used in conjunction with the general requirements for
Inspection Tests in Subsection A, and with the specific
requirements for Inspection and Tests in Subsection B that
pertain to the method of fabrication used.
UNF-91
UNF-125
APPENDIX NF
CHARACTERISTICS OF THE
NONFERROUS MATERIALS
(INFORMATIVE AND
NONMANDATORY)
REQUIREMENTS FOR
PENETRAMETER
NF-1
PURPOSE
This Appendix summarizes the major properties and
fabricating techniques suitable for the nonferrous materials.
WELDING TEST PLATES
If a vessel of welded titanium or zirconium and their
alloys construction incorporates joints of Category A or B
as described in UW-3, a production test plate of the same
specification, grade, and thickness shall be made of sufficient size to provide at least one face and one root bend
specimen or two side bend specimens dependent upon plate
thickness. Where longitudinal joints are involved, the test
1
GENERAL VESSELS
The provisions for pressure relief devices in UG-125
through UG-136 shall apply without supplement to pressure vessels constructed of nonferrous materials.
If the filler metal is radiographically similar1 to the base
metal, the penetrameter may be placed adjacent to the weld;
otherwise it shall be placed on the deposited weld metal.
UNF-95
GENERAL
NF-2
GENERAL
The nonferrous materials can be formed and fabricated
into a variety of types of assemblies with the same types
of fabricating equipment as are used for steel. The details
of some fabricating procedures vary among the several
nonferrous materials and differ from those used for steel
This is defined in Section V, SE-142, 4.1.1 and Appendix A1.
203
2010 SECTION VIII — DIVISION 1
because of differences in the inherent mechanical properties of these materials. Detailed information regarding procedures best suited to the several metals may be obtained
from the literature of the material producers, and from
other reliable sources such as the latest editions of handbooks issued by the American Welding Society and the
American Society for Metals.
NF-3
material producers and the Metals Handbook for conditions
to give optimum results.
NF-9
The commonly used gas processes for welding aluminum-base materials employ oxyhydrogen or oxyacetylene
flames whereas only the latter produces sufficient heat for
welding the copper-base and nickel-base alloys. For the
aluminum, nickel and cupro-nickel alloys a neutral to
slightly reducing flame should be used, whereas for copper
base materials the flame should be neutral to slightly oxidizing. A suitable flux, applied to the welding rod and the
work, shall be used except that no flux is required for
nickel. Boron-free and phosphorus-free fluxes are required
for nickel–copper alloy and for nickel–chromium–iron
alloy. Residual deposits of flux shall be removed.
PROPERTIES
The specified mechanical properties, as listed in Tables
1B and 3 of Section II, Part D, show a wide range of
strengths. The maximum allowable stress values show a
correspondingly wide range and a variable relationship to
service temperature. The maximum temperature listed for
any material is the temperature above which that material
is not customarily used. Section II, Part D, Table PRD
provides Poisson’s ratios and densities for ferrous and nonferrous materials.
NF-10
NF-4
MAGNETIC PROPERTIES
ELEVATED TEMPERATURE
EFFECTS
NF-11
See Appendix A, A-420, of Section II, Part D.
NF-6
LOW TEMPERATURE BEHAVIOR
THERMAL CUTTING
NF-12
In general, nonferrous materials cannot be cut by the
conventional oxyacetylene cutting equipment commonly
used for steel. They may be melted and cut by oxyacetylene, powder cutting carbon arc, oxygen arc, and other
means. When such thermal means for cutting are employed
a shallow contaminated area adjacent to the cut results.
This contamination should be removed by grinding,
machining, or other mechanical means after thermal cutting
and prior to use or further fabrication by welding.
NF-8
INERT GAS METAL ARC WELDING
Both the consumable and nonconsumable electrode processes are particularly advantageous for use with the nonferrous materials. Best results are obtained through the use
of special filler metals.
See Appendix A, A-430, of Section II, Part D.
NF-7
METAL ARC WELDING
Metal arc welds can be made with standard dc equipment
using reversed polarity (electrode-positive) and coated
electrodes. A slightly greater included angle in butt welds
for adequate manipulation of the electrode is required.
See Appendix A, A-410, of Section II, Part D.
NF-5
GAS WELDING
RESISTANCE WELDING
Electric resistance welding, which includes spot, line or
seam, and butt or flash welding, can be used with the
nonferrous materials. Proper equipment and technique are
required for making satisfactory welds.
NF-13
CORROSION
See Appendix A, A-440, of Section II, Part D.
MACHINING
NF-14
The nonferrous materials can be machined with properly
sharpened tools of high-speed steel or cemented-carbide
tools. A coolant is necessary and should be used copiously.
In general, the tools should have more side and top rake
than required for cutting steel and the edges should be
keen and smooth. Comparatively high speeds and fine feeds
give best results. Information can be obtained from the
SPECIAL COMMENTS
(a) Aluminum. See Appendix A, A-451, of Section II,
Part D.
(b) Nickel. See Appendix A, A-452, of Section II,
Part D.
(c) Titanium or Zirconium. See Appendix A, A-453, of
Section II, Part D.
204
2010 SECTION VIII — DIVISION 1
PART UHA
REQUIREMENTS FOR PRESSURE VESSELS
CONSTRUCTED OF HIGH ALLOY STEEL
stress values at different temperatures is given in Section
II, Part D, Table 3 (for bolting) and Table 1A (for other
materials). These stress values are to be multiplied by the
casting quality factors of UG-24. Castings that are to be
welded shall be of weldable grade.
(b) Cast high alloy steel flanges and fittings complying
with ASME B16.5 shall be used within the ratings assigned
in these standards.
GENERAL
UHA-1
SCOPE
The rules in Part UHA are applicable to pressure vessels
and vessel parts that are constructed of high alloy steel
and shall be used in conjunction with the general requirements in Subsection A, and with the specific requirements
in Subsection B that pertain to the method of fabrication
used.
UHA-5
MATERIALS
USES
UHA-11
Some of the uses of high alloy steel are to resist corrosion, to avoid contamination of contents with iron, to facilitate cleaning of vessels for processing foods, to provide
strength or scaling resistance at high temperatures, and to
provide impact resistance at low temperatures.
UHA-6
(a) All materials subject to stress due to pressure shall
conform to one of the specifications given in Section II,
and shall be limited to those listed in Table UHA-23 except
as otherwise provided in (b) and UG-4.
(b) The specifications listed in Tables 1A and 3 of Section II, Part D do not use a uniform system for designating
the Grade number of materials that have approximately
the same range of chemical composition. To provide a
uniform system of reference, these tables include a column
of UNS (Unified Numbering System) numbers assigned
to identify the various alloy compositions. When these
particular UNS numbers were assigned, the familiar AISI
type numbers for stainless steels were incorporated into
the designation. These type numbers are used in the rules
of Part UHA whenever reference is made to materials
of approximately the same chemical composition that are
furnished under more than one approved specification or
in more than one product form.
CONDITIONS OF SERVICE
Specific chemical compositions, heat treatment procedures, fabrication requirements, and supplementary tests
may be required to assure that the vessel will be in its
most favorable condition for the intended service. This is
particularly true for vessels subject to severe corrosion.
These rules do not indicate the selection of an alloy suitable
for the intended service or the amount of the corrosion
allowance to be provided.
It is recommended that users assure themselves by appropriate tests, or otherwise, that the high alloy steel selected
and its heat treatment during fabrication will be suitable
for the intended service both with respect to corrosion
resistance and to retention of satisfactory mechanical properties during the desired service life. (See Appendix HA,
Suggestions on the Selection and Treatment of Austenitic
Chromium–Nickel Steels.)
UHA-8
GENERAL
UHA-12
BOLT MATERIALS
(a) Approved specifications for bolt materials of carbon
steel and low alloy steel are listed in Table UCS-23 and of
high alloy steel in Table UHA-23. A tabulation of allowable
stress values at different temperatures (see UG-12) is given
in Table 3 of Section II, Part D.
(b) Nonferrous bolts, studs, and nuts may be used provided they are suitable for the application. They shall conform to the requirements of Part UNF.
MATERIAL
(a) Approved specifications for castings of high alloy
steel are given in Table UHA-23. A tabulation of allowable
205
2010 SECTION VIII — DIVISION 1
TABLE UHA-23
HIGH ALLOY STEEL
Spec.
No.
UNS
No.
SA-182
S20910
S21904
S30400
S30403
S30409
S30815
S31000
S31050
S31254
S31600
S31603
S31609
S31700
S31703
S31803
S32100
S32109
S32750
S32750
S34700
S34709
S34800
S34809
S39274
S41000
S44627
FXM-19
FXM-11
F304
F304L
F304H
F45
F310
F310MoLN
F44
F316
F316L
F316H
F317
F317L
F51
F321
F321H
..
F53
F347
F347H
F348
F348H
F54
F6a Cl. 1 & 2
FXM-27Cb
S21800
S30400
S30451
S30500
S31600
S31651
S32100
S34700
S41000
B8S, B8SA
B8 Cl. 1 & 2
B8NA Cl. 1A
B8P Cl. 1 & 2
B8M Cl. 1 & 2,
B8M2 Cl. 2
B8MNA Cl. 1A
B8T Cl. 1 & 2
B8C Cl. 1 & 2
B6
S20910
S30400
S30403
S30409
S30451
S30815
S30908
S30909
S30940
S31008
S31009
S31040
S31050
S31277
S31600
S31603
S31609
S31651
S31725
S32100
S32109
S34700
S34709
S34800
XM-19
TP304
TP304L
TP304H
TP304N
...
TP309S
TP309H
TP309Cb
TP310S
TP310H
TP310Cb
TP310MoLN
...
TP316
TP316L
TP316H
TP316N
...
TP321
TP321H
TP347
TP347H
TP348
SA-193
SA-213
Type/Grade
Spec.
No.
UNS
No.
Type/Grade
S34809
S38100
TP348H
XM-15
SA-217
J91150
CA15
SA-240
S20100
S20153
S20400
S20910
S24000
S30100
S30200
S30400
S30403
S30409
S30451
S30815
S30908
S30909
S30940
S31008
S31009
S31040
S31050
S31200
S31254
S31260
S31277
S31600
S31603
S31609
S31635
S31640
S31651
S31700
S31703
S31725
S31803
S32100
S32109
S32304
S32550
S32750
S32900
S32906
S32950
S34700
S34709
S34800
S38100
S40500
S40910
S40920
S40930
S41000
S41008
S42900
S43000
S44000
S44626
201-1, 201-2
201LN
204
XM-19
XM-29
301
302
304
304L
304H
304N
...
309S
309H
309Cb
310S
310H
310Cb
310MoLN
...
...
...
...
316
316L
316H
316Ti
316Cb
316N
317
317L
...
...
321
321H
...
...
...
329
...
...
347
347H
348
XM-15
405
...
...
...
410
410S
429
430
...
XM-33
206
Spec.
No.
UNS
No.
Type/Grade
S44627
S44635
S44660
S44700
S44800
XM-27
...
26-3-3
...
...
SA-249
S20910
S24000
S30400
S30403
S30409
S30451
S30815
S30908
S30909
S30940
S31008
S31009
S31040
S31050
S31254
S31277
S31600
S31603
S31609
S31651
S31700
S31703
S31725
S32100
S32109
S34700
S34709
S34800
S34809
S38100
TPXM-19
TPXM-29
TP304
TP304L
TP304H
TP304N
...
TP309S
TP309H
TP309Cb
TP310S
TP310H
TP310Cb
TP310MoLN
...
...
TP316
TP316L
TP316H
TP316N
TP317
TP317L
...
TP321
TP321H
TP347
TP347H
TP348
TP348H
TPXM-15
SA-268
S40500
S40800
S40900
S41000
S42900
S43000
S43035
S43036
S44400
S44600
S44626
S44627
S44635
S44660
S44700
S44735
S44800
TP405
...
TP409
TP410
TP429
TP430
TP439
TP430Ti
...
TP446-1,
TP446-2
XM-33
XM-27
...
26-3-3
29-4
...
29-4-2
S20910
S21904
S24000
S30400
TPXM-19
TPXM-11
TPXM-29
TP304
SA-312
2010 SECTION VIII — DIVISION 1
TABLE UHA-23
HIGH ALLOY STEEL (CONT’D)
Spec.
No.
SA-320
UNS
No.
S30403
S30409
S30451
S30815
S30908
S30909
S30940
S31008
S31009
S31040
S31050
S31254
S31600
S31603
S31609
S31651
S31700
S31703
S31725
S32100
S32109
S34700
S34709
S34800
S34809
S38100
TP304L
TP304H
TP304N
...
TP309S
TP309H
TP309Cb
TP310S
TP310H
TP310Cb
TP310MoLN
...
TP316
TP316L
TP316H
TP316N
TP317
TP317L
...
TP321
TP321H
TP347
TP347H
TP348
TP348H
TPXM-15
S30323
B8F Cl. 1,
B8FA Cl. 1A
B8 Cl. 1 & 2,
B8A Cl. 1A
B8M Cl. 1 & 2,
B8MA Cl. 1A
B8T Cl. 1 & 2
B8C Cl. 1 & 2,
B8CA Cl. 1A
S30400
S31600
S32100
S34700
SA-351
Type/Grade
J92500
J92590
J92600
J92710
J92800
J92900
J93000
J93254
J93400
J93402
J93790
J94202
...
J94651
J95150
CF3, CF3A
CF10
CF8, CF8A
CF8C
CF3M
CF8M
CG8M
CK3MCuN
CH8
CH20
CG6MMN
CK20
CT15C
CN-3MN
CN7M
Spec.
No.
UNS
No.
SA-358
S31254
S31725
...
...
SA-376
S30400
S30409
S30451
S31600
S31609
S31651
S31725
S32100
S32109
S34700
S34709
S34800
TP304
TP304H
TP304N
TP316
TP316H
TP316N
...
TP321
TP321H
TP347
TP347H
TP348
SA-403
S20910
S30400
S30403
S30409
S30451
S30900
S31008
S31600
S31603
S31609
S31651
S31700
S31703
S32100
S32109
S34700
S34709
S34800
S34809
XM-19
304
304L
304H
304N
309
310S
316
316L
316H
316N
317
317L
321
321H
347
347H
348
348H
S31725
S63198
...
651 Cl. A &
B
660 Cl. A &
B
SA-409
SA-453
S66286
SA-479
S20910
S24000
S30200
S30400
S30403
S30409
S30815
S30908
S30909
S30940
S31008
Type/Grade
XM-19
XM-29
302
304
304L
304H
...
309S
309H
309Cb
310S
207
(10)
Spec.
No.
UNS
No.
Type/Grade
S31009
S31040
S31600
S31603
S31725
S32109
S31803
S32100
S32550
S32906
S34700
S34800
S40500
S41000
S43000
S43035
S44627
S44700
S44800
310H
310Cb
316
316L
...
321H
...
321
...
...
347
348
405
410
430
439
XM-27
...
...
SA-564
S17400
630
SA-638
S66286
660
SA-666
S20100
S21904
201-1, 201-2
XM-11
SA-688
S24000
S30400
S30403
S30451
S31600
S31603
TPXM-29
TP304
TP304L
TP304N
TP316
TP316L
SA-705
SA-731
S17400
S44626
S44627
630
TPXM-33
TPXM-27
SA-747
SA-789
J92180
S31260
S31500
S31803
S32304
S32550
S32750
S32900
S32906
CB7Cu-1
...
...
...
...
...
...
...
...
2010 SECTION VIII — DIVISION 1
TABLE UHA-23
HIGH ALLOY STEEL (CONT’D)
Spec.
No.
SA-790
SA-803
SA-813
UNS
No.
Type/Grade
S32950
S39274
S31260
S31500
S31803
S32304
S32550
S32750
S32900
S32906
S32950
S39274
...
...
...
...
...
...
S43035
S44660
S30908
S30940
S31008
S31040
TP439
26-3-3
TP309S
TP309Cb
TP310S
TP310Cb
...
...
...
...
...
Spec.
No.
UNS
No.
SA-814
S30908
S30940
S31008
S31040
TP309S
TP309Cb
TP310S
TP310Cb
SA-815
...
SA-965
S31803
S21904
S30400
S30403
S30409
S30451
S31000
S31600
S31603
S31609
S31651
S32100
S32109
...
FXM-11
F304
F304L
F304H
F304N
F310
F316
F316L
F316H
F316N
F321
F321H
Spec.
No.
Type/Grade
SA-995
SA-1010
SA/EN 10028-7
SA/JIS G4303
UNS
No.
Type/Grade
S34700
S34709
S34800
S34809
F347
F347H
F348
F348H
J93345
S41003
...
...
...
...
...
...
...
...
...
...
...
2A
40, 50
X5 CrNi 18-10 (1)
X5 CrNiMo 17-12-2 (2)
SUS302
SUS304
SUS304L
SUS310S
SUS316
SUS316L
SUS321
SUS347
SUS405
GENERAL NOTE: Maximum allowable stress values in tension for the materials listed in the above table are contained in Subpart 1 of Section
II, Part D (see UG-23).
NOTES:
(1) X5 CrNi 18-10 shall be considered as Type 309 for the rules of this Part.
(2) X5 CrNiMo 17-12-2 shall be considered as Type 316 for the rules of this Part.
UHA-13
NUTS AND WASHERS
interpolated for intermediate temperatures [see UG-23 and
UG-31(a)].
(b) Shells of pressure vessels may be made from welded
pipe or tubing listed in Table UHA-23.
(c) For vessels designed to operate at a temperature
below −20°F (−30°C), the allowable stress values to be
used in design shall not exceed those given in Table 1A
or 3 of Section II, Part D for temperatures of −20°F to
100°F (−30°C to 40°C).
Nuts and washers shall conform to the requirements in
UCS-11.
DESIGN
UHA-20
GENERAL
The rules in the following paragraphs apply specifically
to the design of pressure vessels and vessel parts that
are constructed of high alloy steel and shall be used in
conjunction with the general requirements for Design in
Subsection A, and with the specific requirements for
Design in Subsection B that pertain to the method of fabrication used.
UHA-21
UHA-28
(a) Cylindrical and spherical shells under external pressure shall be designed by the rules in UG-28, using the
applicable figures in Subpart 3 of Section II, Part D and
the temperature limits of UG-20(c).
(b) Examples illustrating the use of the charts in the
figures for the design of vessels under external pressure
are given in Appendix L.
WELDED JOINTS
When radiographic examination is required for butt
welded joints by UHA-33, joints of Categories A and B
(see UW-3) shall be of Type Nos. (1) and (2) of Table
UW-12.
UHA-23
THICKNESS OF SHELLS UNDER
EXTERNAL PRESSURE
MAXIMUM ALLOWABLE STRESS
VALUES
UHA-29
(a) Tables 3 (for bolting) and 1A (for other materials)
of Section II, Part D give the maximum allowable stress
values at the temperatures indicated for the materials conforming to the specifications listed therein. Values may be
STIFFENING RINGS FOR SHELLS
UNDER EXTERNAL PRESSURE
Rules covering the design of stiffening rings are given
in UG-29. An example illustrating the use of these rules
is given in Appendix L.
208
2010 SECTION VIII — DIVISION 1
UHA-30
ATTACHMENT OF STIFFENING
RINGS TO SHELL
temperature of the pressure part shall control. Ferritic steel
parts, when used in conjunction with austenitic chromium–
nickel stainless steel parts or austenitic /ferritic duplex
steel, shall not be subjected to the solution heat treatment
described in UHA-105(b).
(d) The operation of postweld heat treatment shall be
carried out by one of the procedures given in UW-40 in
accordance with the requirements of UCS-56(d) except as
modified by the Notes to Table UHA-32.
(e) Vessels or parts of vessels that have been postweld
heat treated in accordance with the requirements of this
paragraph shall again be postweld heat treated after repairs
have been made.
Rules covering the attachment of stiffening rings are
given in UG-30.
UHA-31
FORMED HEADS, PRESSURE ON
CONVEX SIDE
Ellipsoidal, torispherical, hemispherical, and conical
heads, having pressure on the convex side (minus heads),
shall be designed by the rules of UG-33, using the figures
for high alloy steels or Fig. CS-2 in Subpart 3 of Section
II, Part D. Examples illustrating the application of this
paragraph are given in Appendix L.
UHA-32
UHA-33
RADIOGRAPHIC EXAMINATION
(a) The requirements for radiographing prescribed in
UW-11, UW-51, and UW-52 shall apply in high alloy
vessels, except as provided in (b) below. (See UHA-21.)
(b) Butt welded joints in vessels constructed of materials conforming to Type 405 welded with straight chromium
electrodes, and to Types 410, 429, and 430 welded with
any electrode, shall be radiographed in all thicknesses. The
final radiographs of all straight chromium ferritic welds
including major repairs to these welds shall be made after
postweld heat treatment has been performed.
(c) Butt welded joints in vessels constructed of austenitic chromium–nickel stainless steels which are radiographed because of the thickness requirements of UW-11,
or for lesser thicknesses where the joint efficiency reflects
the credit for radiographic examination of Table UW-12,
shall be radiographed following post heating if such is
performed.
REQUIREMENTS FOR POSTWELD
HEAT TREATMENT
(a) Before applying the detailed requirements and
exemptions in these paragraphs, satisfactory weld procedure qualifications of the procedures to be used shall be
performed in accordance with all the essential variables of
Section IX including conditions of postweld heat treatment
or lack of postweld heat treatment and including other
restrictions listed below. Welds in pressure vessels or pressure vessel parts shall be given a postweld heat treatment
at a temperature not less than specified in Table UHA32 when the nominal thickness, as defined in UW-40(f),
including corrosion allowance, exceeds the limits in the
Notes to Table UHA-32. The exemptions provided for in
the Notes to Table UHA-32 are not permitted when postweld heat treatment is a service requirement as set forth
in UHA-51 and UW-2, when welding ferritic materials
greater than 1⁄8 in. (3 mm) thick with the electron beam
welding process, or when welding P-Nos. 6 and 7 (except
for Type 405 and Type 410S) materials of any thickness
using the inertia and continuous drive friction welding
processes. The materials in Table UHA-32 are listed in
accordance with the Section IX P-Number material groupings of QW-432 and are also listed in Table UHA-23.
(b) Holding temperatures and / or holding times in
excess of the minimum values given in Table UHA-32
may be used. The holding time at temperature as specified
in Table UHA-32 need not be continuous. It may be an
accumulation of time of multiple postweld heat treat cycles.
Long time exposure to postweld heat treatment temperatures may cause sigma phase formation (see UHA-104).
(c) When pressure parts of two different P-Number
groups are joined by welding, the postweld heat treatment
shall be that specified in either of Tables UHA-32 or
UCS-56, with applicable notes, for the material requiring
the higher postweld temperature. When nonpressure parts
are welded to pressure parts, the postweld heat treatment
UHA-34
LIQUID PENETRANT EXAMINATION
All austenitic chromium–nickel alloy steel and
austenitic /ferritic duplex steel welds, both groove and fillet, which exceed a nominal size of 3⁄4 in. (19 mm), as
defined in UW-40(f), shall be examined for the detection
of cracks by the liquid penetrant method. This examination
shall be made following heat treatment if heat treatment
is performed. All cracks shall be eliminated.
FABRICATION
UHA-40
GENERAL
The rules in the following paragraphs apply specifically
to the fabrication of pressure vessels and vessel parts that
are constructed of high alloy steel and shall be used in
conjunction with the general requirements for Fabrication
in Subsection A, and with the specific requirements for
Fabrication in Subsection B that pertain to the method of
fabrication used.
UHA-42
WELD METAL COMPOSITION
Welds that are exposed to the corrosive action of the
contents of the vessel should have a resistance to corrosion
209
2010 SECTION VIII — DIVISION 1
TABLE UHA-32
POSTWELD HEAT TREATMENT REQUIREMENTS FOR HIGH ALLOY STEELS
Material
P-No. 6
Gr. Nos. 1, 2, 3
Normal Holding
Temperature,
°F (°C),
Minimum
1400 (760)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See TF-720(d)]
Up to 2 in.
(50 mm)
Over 2 in. to 5 in.
(50 mm to 125 mm)
1 hr/in. (25 mm),
15 min minimum
2 hr plus 15 min for each
additional inch (25 mm)
over 2 in. (50 mm)
Over 5 in.
(125 mm)
2 hr plus 15 min for each
additional inch (25 mm)
over 2 in. (50 mm)
NOTES:
(1) Postweld heat treatment is not required for vessels constructed of Type 410 material for SA-182 Grade F6a, SA-240, SA-268, and SA-479
with carbon content not to exceed 0.08% and welded with electrodes that produce an austenitic chromium–nickel weld deposit or a non-airhardening nickel–chromium–iron weld deposit, provided the plate thickness at the welded joint does not exceed 3⁄8 in. (10 mm), and for
thicknesses over 3⁄8 in. (10 mm) to 11⁄2 in. (38 mm) provided a preheat of 450°F (230°C) is maintained during welding and that the joints
are completely radiographed.
(2) Postweld heat treatment shall be performed as prescribed in UW-40 and UCS-56(e).
Material
P-No. 7
Gr. Nos. 1, 2
Normal Holding
Temperature,
°F (°C),
Minimum
1350 (730)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UHA-32(d)]
Up to 2 in.
(50 mm)
Over 2 in. to 5 in.
(50 mm to 125 mm)
1 hr/in. (25 mm),
15 min minimum
2 hr plus 15 min for each
additional inch (25 mm)
over 2 in. (50 mm)
Over 5 in.
(125 mm)
2 hr plus 15 min for each
additional inch (25 mm)
over 2 in. (50 mm)
NOTES:
(1) Postweld heat treatment is not required for vessels constructed of SA-1010 UNS S41003 Type 405, Type 410S, or Type 430 Ti materials
for SA-240 and SA-268 with carbon content not to exceed 0.08%, welded with electrodes that produce an austenitic–chromium–nickel weld
deposit or a non-air-hardening nickel–chromium–iron weld deposit, provided the plate thickness at the welded joint does not exceed 3⁄8 in. (10
mm) and for thicknesses over 3⁄8 in. (10 mm) to 11⁄2 in. (38 mm) provided a preheat of 450°F (230°C) is maintained during welding and that
the joints are completely radiographed.
(2) Postweld heat treatment shall be performed as prescribed in UW-40 and UCS-56(e) except that the cooling rate shall be a maximum of
100°F (56°C)/hr in the range above 1200°F (650°C) after which the cooling rate shall be sufficiently rapid to prevent embrittlement.
(3) Postweld heat treatment is not required for vessels constructed of Grade TP XM-8 material for SA-268 and SA-479 or of Grade TP 18Cr–
2Mo for SA-240 and SA-268.
Material
P-No. 8
Gr. Nos. 1, 2, 3, 4
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UHA-32(d)]
Normal Holding
Temperature,
°F (°C),
Minimum
Up to 2 in.
(50 mm)
Over 2 in. to 5 in.
(50 mm to 125 mm)
Over 5 in.
(125 mm)
...
...
...
...
NOTE:
(1) Postweld heat treatment is neither required nor prohibited for joints between austenitic stainless steels of the P-No. 8 group. See nonmandatory
Appendix HA, UHA-100 to UHA-108, inclusive.
210
2010 SECTION VIII — DIVISION 1
TABLE UHA-32
POSTWELD HEAT TREATMENT REQUIREMENTS FOR HIGH ALLOY STEELS (CONT’D)
Material
P-No. 10H
Gr. No. 1
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UHA-32(d)]
Normal Holding
Temperature,
°F (°C),
Minimum
Up to 2 in.
(50 mm)
Over 2 in. to 5 in.
(50 mm to 125 mm)
Over 5 in.
(125 mm)
...
...
...
...
NOTE:
(1) For the austenitic-ferritic wrought or cast duplex stainless steels listed below, postweld heat treatment is neither required nor prohibited, but
any heat treatment applied shall be performed as listed below and followed by liquid quenching or rapid cooling by other means:
Alloy
S32550
S31260 and S31803
S32900 (0.08 max. C)
S31200
S31500
S32304
J93345
S32750
S32950
S39274
Material
P-No. 10I
Gr. No. 1
Normal Holding
Temperature,
°F (°C),
Minimum
1350 (730)
Postweld Heat Treatment Temperature, °F
(°C)
1900–2050
1870–2010
1725–1750
1900–2000
1785–1875
1740–1920
2050 minimum
1800–2060
1825–1875
1920–2060
(1040–1120)
(1020–1100)
(940–955)
(1040–1095)
(975–1025)
(950–1050)
(1120 minimum)
(980–1130)
(1000–1025)
(1050–1130)
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UHA-32(d)]
Up to 2 in.
(50 mm)
Over 2 in. to 5 in.
(50 mm to 125 mm)
Over 5 in.
(125 mm)
1 hr/in. (25 mm),
15 min minimum
1 hr/in. (25 mm)
1 hr/in. (25 mm)
NOTES:
(1) Postweld heat treatment shall be performed as prescribed in UW-40 and UCS-56(e) except that the cooling rate shall be a maximum of
100°F (56°C)/hr in the range above 1200°F (650°C) after which the cooling rate shall be rapid to prevent embrittlement.
(2) Postweld heat treatment is neither required nor prohibited for a thickness of 1⁄2 in. (13 mm) or less.
(3) For Alloy S44635, the rules for ferritic chromium stainless steel shall apply, except that postweld heat treatment is neither prohibited nor
required. If heat treatment is performed after forming or welding, it shall be performed at 1850°F (1010°C) minimum followed by rapid
cooling to below 800°F (430°C).
Material
P-No. 10K
Gr. No. 1
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UHA-32(d)]
Normal Holding
Temperature,
°F (°C),
Minimum
Up to 2 in.
(50 mm)
Over 2 in. to 5 in.
(50 mm to 125 mm)
Over 5 in.
(125 mm)
...
...
...
...
NOTE:
(1) For Alloy S44660, the rules for ferritic chromium stainless steel shall apply, except that postweld heat treatment is neither required nor
prohibited. If heat treatment is performed after forming or welding, it shall be performed at 1500°F to 1950°F (816°C to 1066°C) for a
period not to exceed 10 min followed by rapid cooling.
211
2010 SECTION VIII — DIVISION 1
that is not substantially less than that of the base metal.
The use of filler metal that will deposit weld metal with
practically the same composition as the material joined is
recommended. When the manufacturer is of the opinion
that a physically better joint can be made by departure
from these limits, filler metal of a different composition
may be used provided the strength of the weld metal at
the operating temperature is not appreciably less than that
of the high alloy material to be welded, and the user is
satisfied that its resistance to corrosion is satisfactory for
the intended service. The columbium content of weld metal
shall not exceed 1.00%, except that ENiCrMo-3,
ERNiCrMo-3, and ENiCrMo-12 weld filler metal made to
SFA-5.11 and SFA-5.14 may be used to weld S31254,
S31603, S31703, S31725, and S31726 to a maximum
design temperature of 900°F (482°C).
(10)
UHA-44
where
R p nominal bending radius to centerline of pipe or
tube
Rf p mean radius after forming
Ro p original radius (equal to infinity for a flat plate)
r p nominal outside radius of pipe or tube
t p nominal thickness of the plate, pipe, or tube before
forming
tA p measured average wall thickness of pipe or tube
tB p measured minimum wall thickness of the extrados
of the bend
UHA-44(b) When forming strains cannot be calculated
as shown in (a) above, the Manufacturer shall have the
responsibility to determine the maximum forming strain.
For flares, swages, or upsets, heat treatment in accordance
with Table UHA-44 shall apply, regardless of the amount
of strain.
REQUIREMENTS FOR
POSTFABRICATION HEAT
TREATMENT DUE TO STRAINING
INSPECTION AND TESTS
UHA-44(a) The following rules shall apply in addition
to general rules for forming given in UHA-40.
UHA-44(a)(1) If the following conditions prevail, the
cold formed areas of pressure-retaining components manufactured of austenitic alloys shall be solution annealed by
heating at the temperatures given in Table UHA-44 for 20
min/in. (20 min/25 mm) of thickness or 10 min, whichever
is greater, followed by rapid cooling:
(a) the finishing-forming temperature is below the
minimum heat-treating temperature given in Table UHA44; and
(b) the design metal temperature and the forming
strains exceed the limits shown in Table UHA-44.
UHA-44(a)(2) Forming strains shall be calculated as
follows:
(a) cylinders formed from plate:
% strain p
冢
50t
R
1− f
Rf
Ro
UHA-50
The rules in the following paragraphs apply specifically
to the inspection and testing of pressure vessels and vessel
parts that are constructed of high alloy steel and shall
be used in conjunction with the general requirements for
Inspection and Tests in Subsection A, and with the specific
requirements for Inspection and Tests in Subsection B that
pertain to the method of fabrication used.
UHA-51
冢
75t
R
1− f
Rf
Ro
冣
冣
(c) tube and pipe bends: the larger of
% strain p
100r
R
or
% strain p
冢
IMPACT TESTS
Impact tests, as prescribed in UHA-51(a), shall be performed on materials listed in Table UHA-23 for all combinations of materials and minimum design metal
temperatures (MDMTs) except as exempted in UHA-51(d),
(e), (f), (g), (h), or (i). Impact tests are not required where
the maximum obtainable Charpy specimen has a width
along the notch less than 0.099 in. (2.5 mm).
UHA-51(a) Required Impact Testing of Base Metal,
Heat-Affected Zones, and Weld Metal
UHA-51(a)(1) Impact test shall be made from sets of
three specimens. A set shall be tested from the base metal,
a set shall be tested from the heat affected zone, and a set
shall be tested from the weld metal. Specimens shall be
subjected to the same thermal treatments1 as the part or
vessel that the specimens represent. Test procedures, size,
location, and orientation of the specimens shall be the same
as required in UG-84.
(b) spherical or dished heads formed from plate:
% strain p
GENERAL
冣
tA − t B
100
tA
1
Thermal treatments of materials are not intended to include warming
to temperatures not exceeding 600°F (315°C), thermal cutting, or welding.
212
(10)
2010 SECTION VIII — DIVISION 1
TABLE UHA-44
POSTFABRICATION STRAIN LIMITS AND REQUIRED HEAT TREATMENT
(10)
Limitations in Lower Temperature Range
For Design Temperature,
°F (°C)
Grade
UNS
Number
201-1
S20100
heads
201-1 S20100
all others
201-2 S20100
heads
201-2 S20100
all others
201LN S20153
heads
201LN S20153
all others
204
S20400
heads
204
S20400
all others
Limitations in Higher
Temperature Range
Exceeding
But Less
Than or
Equal to
And
Forming
Strains
Exceeding,
%
For Design
Temperature,
°F (°C),
Exceeding
And Forming
Strains
Exceeding,
%
Minimum Heat-Treatment
Temperature, °F (°C), When
Design Temperature and
Forming Strain Limits Are
Exceeded [Notes (1) and (2)]
All
All
All
All
All
1,950 (1 065)
All
All
4
All
4
1,950 (1 065)
All
All
All
All
All
1,950 (1 065)
All
All
4
All
4
1,950 (1 065)
All
All
All
All
All
1,950 (1 065)
All
All
4
All
4
1,950 (1 065)
All
All
All
All
All
1,950 (1 065)
All
All
4
All
4
1,950 (1 065)
304
304H
304N
S30400
S30409
S30451
1,075 (580)
1,075 (580)
1,075 (580)
1,250 (675)
1,250 (675)
1,250 (675)
20
20
15
1,250 (675)
1,250 (675)
1,250 (675)
10
10
10
1,900 (1 040)
1,900 (1 040)
1,900 (1 040)
309S
S30908
1,075 (580)
1,250 (675)
20
1,250 (675)
10
2,000 (1 095)
310H
S31009
1,075 (580)
1,250 (675)
20
1,250 (675)
10
2,000 (1 095)
310S
S31008
1,075 (580)
1,250 (675)
20
1,250 (675)
10
2,000 (1 095)
316
S31600
1,075 (580)
1,250 (675)
20
1,250 (675)
10
1,900 (1 040)
316H
S31609
1,075 (580)
1,250 (675)
20
1,250 (675)
10
1,900 (1 040)
316N
S31651
1,075 (580)
1,250 (675)
15
1,250 (675)
10
1,900 (1 040)
321
S32100
1,000 (540)
1,250 (675)
15 [Note (3)]
1,250 (675)
10
1,900 (1 040)
321H
S32109
1,000 (540)
1,250 (675)
15 [Note (3)]
1,250 (675)
10
2,000 (1 095)
347
S34700
1,000 (540)
1,250 (675)
15
1,250 (675)
10
1,900 (1 040)
347H
S34709
1,000 (540)
1,250 (675)
15
1,250 (675)
10
2,000 (1 095)
348
S34800
1,000 (540)
1,250 (675)
15
1,250 (675)
10
1,900 (1 040)
348H
S34809
1,000 (540)
1,250 (675)
15
1,250 (675)
10
2,000 (1 095)
GENERAL NOTES:
(a) The limits shown are for cylinders formed from plates, spherical or dished heads formed from plate, and tube and pipe bends.
(b) When the forming strains cannot be calculated as shown in UHA-44(a), the forming strain limits shall be half those tabulated in this Table
[see UHA-44(b)].
NOTES:
(1) Rate of cooling from heat-treatment temperature is not subject to specific control limits.
(2) While minimum heat-treatment temperatures are specified, it is recommended that the heat-treatment temperature range be limited to 150°F
(83°C) above that minimum [250°F (140°C) temperature range for 347, 347H, 348, and 348H].
(3) For simple bends of tubes or pipes whose outside diameter is less than 3.5 in. (88 mm), this limit is 20%.
213
2010 SECTION VIII — DIVISION 1
(10)
FIG. UHA-44 DELETED
UHA-51(a)(2) Each of the three specimens tested in
each set shall have a lateral expansion opposite the notch
not less than 0.015 in. (0.38 mm) for MDMTs of −320°F
(−196°C) and warmer.
UHA-51(a)(3) When the MDMT is −320°F (−196°C)
and warmer, and the value of lateral expansion for one
specimen of a set is less than 0.015 in. (0.38 mm) but not
less than 0.010 in. (0.25 mm), a retest of three additional
specimens may be made, each of which must equal or
exceed 0.015 in. (0.38 mm). Such a retest shall be permitted
only when the average value of the three specimens equals
or exceeds 0.015 in. (0.38 mm). If the required values are
not obtained in the retest or if the values in the initial test
are less than minimum required for retest, the material
may be reheat treated. After reheat treatment, new sets of
specimens shall be made and retested; all specimens must
meet the lateral expansion value of 0.015 in. minimum.
UHA-51(a)(4) When the MDMT is colder than
−320°F (−196°C), production welding processes shall be
limited to shielded metal arc welding (SMAW), gas metal
arc welding (GMAW), submerged arc welding (SAW),
plasma arc welding (PAW), and gas tungsten arc welding
(GTAW). Each heat, lot, or batch of filler metal and filler
metal/flux combination shall be pre-use tested as required
by UHA-51(f)(4)(a) through (c). Exemption from pre-use
testing as allowed by UHA-51(f)(4)(d) and (e) is not applicable. Notch toughness testing shall be performed as specified in (a) or (b) below, as appropriate.
(a) If using Type 316L weld filler metal:
(1) each heat of filler metal used in production
shall have a Ferrite Number (FN) not greater than 5, as
measured by a ferritescope or magna gauge calibrated in
accordance with AWS A4.2, or as determined by applying
the chemical composition from the test weld to Fig. ULT82; and
(2) notch toughness testing of the base metal,
weld metal, and heat affected zone (HAZ) shall be conducted using a test temperature of −320°F (−196°C); and
(3) each of the three specimens from each test
set shall have a lateral expansion opposite the notch not
less than 0.021 in. (0.53 mm).
(b) If using filler metals other than Type 316L; or
when the base metal, weld metal, or heat affecteed zone
are unable to meet the requirements of (a) above:
(1) notch toughness testing shall be conducted
at a test temperature not warmer than MDMT, using the
ASTM E 1820 JIC method;
(2) a set of two specimens shall be tested in the
TL orientation with a resulting KIC (J) of not less than
120 ksi冪in. (132 MPa冪m);
(3) each heat or lot of austenitic stainless steel
filler metal used in production shall have a FN not greater
than the FN determined for the test weld.
UHA-51(b) Required Impact Testing for Welding Procedure Qualifications. For welded construction the Welding Procedure Qualification shall include impact tests of
welds and heat affected zones (HAZs) made in accordance
with UG-84(h) and with the requirements of UHA-51(a),
when any of the components 2 of the welded joint are
required to be impact tested by the rules of this Division.
UHA-51(c) Required Impact Testing When Thermal
Treatments Are Performed. Impact tests are required at the
colder of 70°F (20°C) or the MDMT, whenever thermal
treatments1 within the temperature ranges listed for the
following materials are applied:
UHA-51(c)(1) austenitic stainless steels thermally
treated at temperatures between 900°F (480°C) and 1650°F
(900°C); however, Types 304, 304L, 316, and 316L that
are thermally treated at temperatures between 900°F
(480°C) and 1300°F (705°C) are exempt from impact testing provided the MDMT is −20°F (−29°C) or warmer and
vessel (production) impact tests of the thermally treated
weld metal are performed for Category A and B joints;
UHA-51(c)(2) austenitic-ferritic duplex stainless
steels thermally treated at temperatures between 600°F
(315°C) and 1750°F (955°C);
UHA-51(c)(3) ferritic chromium stainless steels thermally treated at temperatures between 800°F (425°C) and
1,350°F (730°C);
UHA-51(c)(4) martensitic chromium stainless steels
thermally treated at temperatures between 800°F (425°C)
and 1,350°F (730°C).
UHA-51(d) Exemptions from Impact Testing for Base
Metals and Heat Affected Zones. Impact testing is not
required for Table UHA-23 base metals for the following
combinations of base metals and heat affected zones (if
welded) and MDMTs, except as modified in UHA-51(c):
UHA-51(d)(1) for austenitic chromium–nickel stainless steels as follows:
(a) Types 304, 304L, 316, 316L, 321 and 347 at
MDMTs of −320°F (−196°C) and warmer;
(b) those types not listed in (d)(1)(a) above and
having a carbon content not exceeding 0.10% at MDMTs
of −320°F (−196°C) and warmer;
(c) having carbon content exceeding 0.10% at
MDMTs of −55°F (−48°C) and warmer;
(d) for castings at MDMTs of −20°F (−29°C) and
warmer;
2
214
Either base metal or weld metal.
2010 SECTION VIII — DIVISION 1
UHA-51(d)(2) for austenitic chromium–manganese–
nickel stainless steels (200 series) as follows:
(a) having a carbon content not exceeding 0.10%
at MDMTs of −320°F (−196°C) and warmer;
(b) having a carbon content exceeding 0.10% at
MDMTs of −55°F (−48°C) and warmer;
(c) for castings at MDMTs of −20°F (−29°C) and
warmer;
UHA-51(d)(3) for the following steels in all product
forms at MDMTs of −20°F (−29°C) and warmer:
(a) austenitic ferritic duplex steels with a nominal
material thickness of 3⁄8 in. (10 mm) and thinner;
(b) ferritic chromium stainless steels with a nominal
material thickness of 1⁄8 in. (3 mm) and thinner;
(c) martensitic chromium stainless steels with a
nominal material thickness of 1⁄4 in. (6 mm) and thinner.
UHA-51(f)(1) The welding processes are limited to
SMAW, SAW, GMAW, GTAW, and PAW.
UHA-51(f)(2) The applicable Welding Procedure
Specifications (WPSs) are supported by Procedure Qualification Records (PQRs) with impact testing in accordance
with the requirements of UHA-51(a) at the MDMT or
colder, or when the applicable PQR is exempted from
impact testing by other provisions of this Division.
UHA-51(f)(3) The weld metal (produced with or
without the addition of filler metal) has a carbon content
not exceeding 0.10%.
UHA-51(f)(4) The weld metal is produced by filler
metal conforming to SFA-5.4, SFA-5.9, SFA-5.11,
SFA-5.14, and SFA-5.22 as modified below.
(a) Each heat and /or lot of welding consumables
to be used in production welding with the SMAW and
GMAW processes shall be pre-use tested by conducting
impact tests at the MDMT or colder. Test coupons shall
be prepared in accordance with Section II, Part C, SFA5.4, A9.3.5 utilizing the WPS to be used in production
welding. Acceptance criteria shall conform with UHA51(a).
(b) Each heat of filler metal and batch of flux combination to be used in production welding with the SAW
process shall be pre-use tested by conducting impact tests
at the MDMT or colder. Test coupons shall be prepared
in accordance with Section II, Part C, SFA-5.4, A9.3.5
utilizing the WPS to be used in production welding.
Acceptance criteria shall conform with UHA-51(a).
(c) Combining more than one welding process or
more than one heat, lot, and /or batch of welding material
into a single test coupon is unacceptable. Pre-use testing
at the MDMT or colder may be conducted by the welding
consumable manufacturer, provided certified mill test
reports are furnished with the consumables.
(d) The following filler metals may be used without
pre-use testing of each heat, lot, and /or batch, provided
that procedure qualification impact testing in accordance
with UG-84(h) at the MDMT or colder is performed using
the same manufacturer brand and type filler metal:
ENiCrFe-2, ENiCrFe-3, ENiCrMo-3, ENiCrMo-4,
ENiCrMo-6, ERNiCr-3, ERNiCrMo-3, ERNiCrMo-4,
SFA-5.4 E310-15 or 16.
(e) The following filler metals may be used without
pre-use testing of each heat and /or lot, provided that procedure qualification impact testing in accordance with
UG-84(h) at the MDMT or colder is performed: ER308L,
ER316L, and ER310 used with the GTAW or PAW processes.
Carbon content as used in (d)(1) and (d)(2) above is as
specified by the purchaser and must be within the limits
of the material specification.
UHA-51(e) Exemptions from Impact Testing for Welding Procedure Qualifications. For Welding Procedure
Qualifications, impact testing is not required for the following combinations of weld metals and MDMTs except as
modified in UHA-51(c):
UHA-51(e)(1) for austenitic-chromium–nickel stainless steel base materials having a carbon content not
exceeding 0.10% welded without the addition of filler
metal, at MDMTs of −155°F (−104°C) and warmer;
UHA-51(e)(2) for austenitic weld metal:
(a) having a carbon content not exceeding 0.10%
and produced with filler metals conforming to SFA-5.4,
SFA-5.9, SFA-5.11, SFA-5.14, and SFA-5.22 at MDMTs
of −155°F (−104°C) and warmer;
(b) having a carbon content exceeding 0.10% and
produced with filler metals conforming to SFA-5.4,
SFA-5.9, SFA-5.11, SFA-5.14, and SFA-5.22 at MDMTs
of −55°F (−48°C) and warmer;
UHA-51(e)(3) for the following weld metal, when the
base metal of similar chemistry is exempt as stated in
UHA-51(d)(3), then the weld metal shall also be exempt
at MDMTs of −20°F (−29°C) and warmer:
(a) austenitic ferritic duplex steels;
(b) ferritic chromium stainless steels;
(c) martensitic chromuim stainless steels.
Carbon content as used in (e)(2) above is for weld metal
produced with the addition of filler metal.
UHA-51(f) Required Impact Testing for Austenitic
Stainless Steel Welding Consumables With MDMTs Colder
Than −155°F (−104°C). For production welds at MDMTs
colder than −155°F (−104°C), all of the following conditions shall be satisfied:
UHA-51(g) Exemption From Impact Testing Because
of Low Stress. Impact testing of materials listed in Table
215
2010 SECTION VIII — DIVISION 1
UHA-23 is not required, except as modified by UHA-51(c),
for vessels when the coincident ratio of design stress3 in
tension to allowable tensile stress is less than 0.35. This
exemption also applies to the welding procedures and production welds for the component.
UHA-51(h) Vessel (Production) Impact Tests
UHA-51(h)(1) For welded construction of duplex
stainless steels, ferritic stainless steels, and martensitic
stainless steels, vessel (production) impact tests in accordance with UG-84(i) are required if the Weld Procedure
Qualification requires impact testing, unless otherwise
exempted by the rules of this Division.
UHA-51(h)(2) When the MDMT is colder than
−320°F (−196°C), vessel (production) impact tests or
ASTM E 1820 JIc tests shall be conducted for austenitic
stainless steels in accordance with UHA-51(a)(4).
UHA-51(i) Vessel (Production) Impact Tests for Autogenous Welds in Austenitic Stainless Steels. For autogenous
welds (welded without filler metal) in austenitic stainless
steels, vessel (production) impact tests are not required
when both of the following conditions are satisfied:
UHA-51(i)(1) The material is solution annealed after
welding.
UHA-51(i)(2) The MDMT is not colder than −320°F
(−196°C).
UHA-52
APPENDIX HA
SUGGESTIONS ON THE SELECTION
AND TREATMENT OF AUSTENITIC
CHROMIUM–NICKEL AND FERRITIC
AND MARTENSITIC HIGH CHROMIUM
STEELS (INFORMATIVE AND
NONMANDATORY)
UHA-100
GENERAL
The selection of the proper metal composition to resist
a given corrosive medium and the choice of the proper
heat treatment and surface preparation of the material
selected are not within the scope of this Division. Appendix
A, A-310 to A-360, of Section II, Part D discusses some
of the factors that should be considered in arriving at a
proper selection.
UHA-101
STRUCTURE
See Appendix A, A-310, of Section II, Part D.
UHA-102
INTERGRANULAR CORROSION
See Appendix A, A-320, of Section II, Part D.
WELDED TEST PLATES
UHA-103
(a) For welded vessels constructed of Type 405 material
which are not postweld heat treated, welded test plates
shall be made to include material from each melt of plate
steel used in the vessel. Plates from two different melts
may be welded together and be represented by a single
test plate.
(b) From each welded test plate there shall be taken
two face-bend test specimens as prescribed in QW-461.2 of
Section IX; these shall meet the requirements of QW-160,
Section IX.
STRESS CORROSION CRACKING
See Appendix A, A-330, of Section II, Part D.
UHA-104
SIGMA PHASE EMBRITTLEMENT
See Appendix A, A-340, of Section II, Part D.
UHA-105
HEAT TREATMENT OF AUSTENITIC
CHROMIUM–NICKEL STEELS
See Appendix A, A-350, of Section II, Part D.
MARKING AND REPORTS
UHA-60
GENERAL
UHA-107
The provisions for marking and reports in UG-115
through UG-120 shall apply without supplement to vessels
constructed of high alloy steels.
The difference between the coefficients of expansion
of the base material and the weld should receive careful
consideration before undertaking the welding of ferritic
type stainless steels with austenitic electrodes for services
involving severe temperature conditions, particularly those
of a cyclic nature.
PRESSURE RELIEF DEVICES
UHA-65
DISSIMILAR WELD METAL
GENERAL
The provisions for pressure relief devices given in
UG-125 through UG-136 shall apply without supplement
to vessels constructed of high alloy steels.
UHA-108
FABRICATION
It is recommended that the user of austenitic chromium–
nickel steel vessels in corrosive service consider the following additional fabrication test.
3
Calculated stress from pressure and nonpressure loadings, including
those listed in UG-22 which result in general primary membrane tensile stress.
216
2010 SECTION VIII — DIVISION 1
A welded guided-bend test specimen should be made
as prescribed in QW-161.2 of Section IX from one of the
heats of material used in the shell. The test plate should
be welded by the procedure used in the longitudinal joints
of the vessel and should be heat treated using the same
temperature cycle as used for the vessel. The operations
on the test plate should be such as to duplicate as closely
as possible the physical conditions of the material in the
vessel itself.
Grind and polish the specimen and immerse it for not
less than 72 hr in a boiling solution consisting of 47 ml
concentrated sulfuric acid and 13 g of crystalline copper
sulfate (CuSO4 · 5H2O) per liter of water. Then bend the
specimen so as to produce an elongation of not less than
20% at a section in the base metal 1⁄4 in. (6 mm) from
the edge of the weld. The metal shall show no sign of
disintegration after bending.
UHA-109
885°F (475°C) EMBRITTLEMENT
See Appendix A, A-360, of Section II, Part D.
217
2010 SECTION VIII — DIVISION 1
PART UCI
REQUIREMENTS FOR PRESSURE VESSELS
CONSTRUCTED OF CAST IRON
(4) 300 psi (2 MPa) at temperatures not greater than
450°F (230°C) for bolted heads, covers, or closures that
do not form a major component of the pressure vessel.
(b) Vessels and vessel parts constructed of stress
relieved material conforming to Classes 40 through 60 of
SA-278 may be used for design pressures up to 250 psi
(1.7 MPa) at temperatures up to 650°F (345°C), provided
the distribution of metal in the pressure containing walls
of the casting is shown to be approximately uniform.
(c) Vessels and vessel parts constructed of stress
relieved material conforming to SA-476 may be used for
design pressures up to 250 psi (1.7 MPa) at temperatures
up to 450°F (230°C).
(d) Cast iron flanges and flanged fittings conforming to
ASME B16.1, Cast Iron Pipe Flanges and Flanged Fittings,
Classes 125 and 250, may be used in whole or in part of
a pressure vessel for pressures not exceeding the American
National Standard ratings at temperatures not exceeding
450°F (230°C).
GENERAL
UCI-1
SCOPE
The rules in Part UCI are applicable to pressure vessels
and vessel parts that are constructed of cast iron, cast
nodular iron having an elongation of less than 15% in 2 in.
(50 mm), or of cast dual metal (see UCI-23 and UCI-29)
except standard pressure parts covered by UG-11(b), and
shall be used in conjunction with the general requirements
in Subsection A insofar as these requirements are applicable to cast material.
UCI-2
SERVICE RESTRICTIONS
Cast iron vessels shall not be used for services as follows:
(a) to contain lethal1 or flammable substances, either
liquid or gaseous;
(b) for unfired steam boilers as defined in U-1(g);
(c) for direct firing [see UW-2(d)].
UCI-3
MATERIALS
PRESSURE–TEMPERATURE
LIMITATIONS
UCI-5
GENERAL
(a) The design pressure for vessels and vessel parts
constructed of any of the classes of cast iron listed in Table
UCI-23 shall not exceed the following values except as
provided in (b) and (c) below:
(1) 160 psi (1.1 MPa) at temperatures not greater than
450°F (230°C) for vessels containing gases, steam, or other
vapors;
(2) 160 psi (1.1 MPa) at temperatures not greater than
375°F (190°C) for vessels containing liquids;
(3) 250 psi (1.7 MPa) for liquids at temperatures less
than their boiling point at design pressure, but in no case
at temperatures exceeding 120°F (50°C);
All cast iron material subject to stress due to pressure
shall conform to one of the specifications given in Section
II and shall be limited to those listed in Table UCI-23
except as otherwise provided in UG-11.
1
By “lethal substances” are meant poisonous gases or liquids of such
a nature that a very small amount of the gas or of the vapor of the liquid
mixed or unmixed with air is dangerous to life, when inhaled. For purposes
of this Division, this class includes substances of this nature which are
stored under pressure or may generate a pressure if stored in a closed
vessel.
DESIGN
UCI-12
BOLT MATERIALS
The requirements for bolts, nuts, and washers shall be
the same as for carbon and low alloy steels in UCS-10 and
UCS-11.
UCI-16
GENERAL
The rules in the following paragraphs apply specifically
to the design of pressure vessels and pressure vessel parts
218
2010 SECTION VIII — DIVISION 1
TABLE UCI-23
MAXIMUM ALLOWABLE STRESS VALUES IN TENSION FOR CAST IRON
Spec.
No.
Class
Specified
Min.
Tensile
Strength,
ksi (MPa)
450°F (230°C)
and Colder
650°F
(345°C)
Ext.
Press.
Chart Fig.
No.
[Note (1)]
SA-667
...
20 (138)
2.0 (13.8)
...
CI-1
SA-278
SA-278
SA-278
SA-278
SA-278
SA-278
SA-278
20
25
30
35
40
45
50
20
25
30
35
40
45
50
2.0
2.5
3.0
3.5
4.0
4.5
5.0
(13.8)
(17.2)
(20.7)
(24.1)
(27.6)
(31.0)
(34.5)
...
...
...
...
4.0 (27.6)
4.5 (31.0)
5.0 (34.5)
CI-1
CI-1
CI-1
CI-1
CI-1
CI-1
CI-1
SA-47
(Grade 3-2510)
50 (345)
5.0 (34.5)
5.0 (34.5)
CI-1
SA-278
SA-278
55
60
55 (379)
60 (414)
5.5 (37.9)
6.0 (41.4)
5.5 (37.9)
6.0 (41.4)
CI-1
CI-1
SA-476
...
80 (552)
8.0 (55.2)
...
CI-1
SA-748
SA-748
SA-748
SA-748
20
25
30
35
16
20
24
28
1.6
2.0
2.4
2.8
...
...
...
...
CI-1
CI-1
CI-1
CI-1
Maximum Allowable Stress, ksi (MPa),
for Metal Temperature Not Exceeding
(138)
(172)
(207)
(241)
(276)
(310)
(345)
(110)
(138)
(165)
(193)
(11.0)
(13.8)
(16.5)
(19.3)
NOTE:
(1) Figure CI-1 is contained in Subpart 3 of Section II, Part D.
of cast iron and shall be used in conjunction with the
general requirements for Design in Subsection A, insofar
as these requirements are applicable to cast materials.
For components for which the Code provides no design
rules, the provisions of UG-19(b) and (c) apply. If a proof
test is performed, the rules of UCI-101 apply.
UCI-23
UCI-28
THICKNESS OF SHELLS UNDER
EXTERNAL PRESSURE
(a) Cylindrical and spherical shells under external pressure shall be designed by the rules in UG-28, using the
applicable figures in Subpart 3 of Section II, Part D and
the temperature limits of UG-20(c).
(b) Examples illustrating the use of the charts in the
figures for the design of vessels under external pressure
are given in Appendix L.
MAXIMUM ALLOWABLE STRESS
VALUES
UCI-29
(a) Table UCI-23 gives the maximum allowable stress
values in tension at the temperatures indicated for castings
conforming to the specifications listed therein. For dual
metal cylinders conforming to SA-667 or SA-748, the maximum calculated stress, including all applicable loadings
of UG-22, shall not exceed the allowable stress given in
Table UCI-23 computed on the basis of the gray cast iron
thickness of the cylinder.
(b) The maximum allowable stress value in bending
shall be 11⁄2 times that permitted in tension, and the maximum allowable stress value in compression shall be two
times that permitted in tension.
DUAL METAL CYLINDERS
The minimum wall thickness of dual metal cylinders
conforming to SA-667 or SA-748 shall be 5 in. (125 mm),
and the outside diameter of such cylinders shall not exceed
36 in. (900 mm).
UCI-32
HEADS WITH PRESSURE ON
CONCAVE SIDE
Heads with pressure on the concave side (plus heads)
shall be designed in accordance with the formulas in UG-32
using the maximum allowable stress value in tension.
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2010 SECTION VIII — DIVISION 1
UCI-33
TABLE UCI-78.1
HEADS WITH PRESSURE ON
CONVEX SIDE
The thickness of heads with pressure on the convex side
(minus heads) shall not be less than the thickness required
in UCI-32 for plus heads under the same pressure nor less
than 0.01 times the inside diameter of the head skirt.
UCI-35
NPS Plug or Equivalent
SPHERICALLY SHAPED COVERS
(HEADS)
(a) Circular cast iron spherically shaped heads with
bolting flanges, similar to Fig. 1-6 sketches (b), (c), and
(d), shall be designed in accordance with the provisions
in 1-6, except that corners and fillets shall comply with
the requirements of UCI-37.
(b) Circular cast iron spherically shaped heads with
bolting flanges other than those described in (a) above shall
be designed in accordance with the following requirements.
(1) The head thickness shall be determined in accordance with the requirements in UG-32.
(2) The spherical and knuckle radii shall conform to
the requirements in UG-32.
(3) Cast iron flanges and flanged fittings conforming
to ASME B16.1 may be used in whole or in part of a
pressure vessel for pressures not exceeding American
National Standard ratings at temperatures not exceeding
450°F (230°C). Other flanges may be designed in accordance with the provisions of Appendix 2 using the allowable stress values in bending.
UCI-36
1
⁄8
⁄4
3
⁄8
1
⁄2
3
⁄4
11
1
7
⁄32
⁄16
1
⁄2
21
⁄32
3
⁄4
(9)
(11)
(13)
(17)
(19)
1
11⁄4
11⁄2
2
13
(21)
(22)
(24)
(25)
⁄16
⁄8
15
⁄16
1
7
(a) Fillets forming the transition between the pressure
containing walls and integral attachments, such as brackets,
lugs, supports, nozzles, flanges, and bosses, shall have a
radius not less than one-half the thickness of the pressure
containing wall adjacent to the attachment.
FABRICATION
UCI-75
GENERAL
The rules in the following paragraphs apply specifically
to the fabrication of pressure vessels and vessel parts of
cast iron and shall be used in conjunction with the general
requirements for Fabrication in Subsection A insofar as
these requirements are applicable to cast materials.
OPENINGS AND REINFORCEMENTS
UCI-78
(a) The dimensional requirements in UG-36 through
UG-46 are applicable to cast iron and shall be used in the
design of openings and reinforcements in pressure vessels
and pressure vessel parts which are cast integrally with the
vessel or vessel part. In no case shall the thickness of
the reinforcement, including the nominal thickness of the
vessel wall, exceed twice the nominal thickness of the
vessel wall.
(b) Cast iron flanges, nozzles, and openings shall not
be attached to steel or nonferrous pressure vessels or pressure parts by welding or brazing, nor shall they be considered to contribute strength to the vessel or part.
UCI-37
Minimum Thickness
of Repaired
Section, in. (mm)
REPAIRS IN CAST IRON
MATERIALS
(a) Imperfections that permit leakage in cast iron materials may be repaired by using threaded plugs provided:
(1) the vessel or vessel parts are to operate within
the limits of UCI-3(a) or (b);
(2) no welding is performed;
(3) the diameter of the plug shall not exceed the diameter of a standard NPS 2 pipe plug;
(4) the plugs, where practical, shall conform in all
dimensions to standard NPS pipe plugs, and in addition
they shall have full thread engagement corresponding to
the thickness of the repaired section. (See Table UCI-78.1.)
Where a tapered plug is impractical because of excess wall
thickness in terms of plug diameter and coincident thread
engagement, other types of plugs may be used provided
both full thread engagement and effective sealing against
pressure are obtained. Where possible, the ends of the plug
should be ground smooth after installation to conform to
the inside and outside contours of the walls of the pressure
vessel or pressure part;
CORNERS AND FILLETS
A liberal radius shall be provided at projecting edges
and in reentrant corners in accordance with good foundry
practice. Abrupt changes in surface contour and in wall
thickness at junctures shall be avoided. Fillets shall conform to the following.
220
2010 SECTION VIII — DIVISION 1
than the larger of 3⁄8 in. (10 mm) or 20% of the thickness
of the section;
(5) the pressure vessel or pressure vessel part meets
the standard hydrostatic test prescribed in UCI-99.
(c) Surface imperfections, such as undue roughness,
which do not permit leakage in cast iron vessels that are
to operate under the limits of UCI-3(a)(3) may be repaired
under (a) or (b) above or by welding. Where welding is
used, the weld and the metal adjacent to it shall be examined
by either the magnetic particle or liquid penetrant method
and shown to be free of linear indications.
TABLE UCI-78.2
Minimum Radius
of Curvature of
Cylinder or
Cone, in. (mm)
NPS Plug or
Equivalent
1
9
⁄16
11
⁄16
11⁄16
11⁄4
⁄8
⁄4
3
⁄8
1
⁄2
3
⁄4
2
1
11⁄4
11⁄2
2
21⁄2
4
51⁄4
81⁄8
1
(14)
(17)
(27)
(32)
(50)
(64)
(100)
(134)
(207)
INSPECTION AND TESTS
UCI-90
(5) the material from which the plug is manufactured
shall conform in all respects to the material specification
which applies to the pressure vessel or pressure vessel part;
(6) the machined surface of the drilled or bored hole
before tapping shall be free from visible defects and the
adjacent metal shown to be sound by radiographic examination;
(7) the thickness of any repaired section in relation
to the size of plug used shall not be less than that given
in Table UCI-78.1;
(8) the minimum radius of curvature of repaired sections of cylinders or cones in relation to the size of plug
used shall not be less than that given in Table UCI-78.2;
(9) the ligament efficiency between any two adjacent
plugs shall not be less than 80% where
p−
Ep
冢
d1 + d 2
2
GENERAL
The rules in the following paragraphs apply specifically
to the inspection and testing of pressure vessels and vessel
parts of cast iron and shall be used in conjunction with the
general requirements for Inspection and Tests in Subsection A insofar as these requirements are applicable to cast
material.
UCI-99
STANDARD HYDROSTATIC TEST
Cast iron pressure vessels shall be hydrostatically tested
by the method prescribed in UG-99 except that the test
pressure shall be two times the maximum allowable working pressure to be marked on the vessel for maximum
allowable working pressures greater than 30 psi (200 kPa)
and 21⁄2 times the maximum allowable working pressure
but not to exceed 60 psi (400 kPa) for maximum allowable
working pressure under 30 psi (200 kPa).
冣
p
and
UCI-101
E p ligament efficiency
p p distance between plug centers
d1, d2 p respective diameters of the two plugs under
consideration
HYDROSTATIC TEST TO
DESTRUCTION
(a) The maximum allowable working pressure of identical cast iron vessels or vessel parts, based on testing one
of them to destruction, limited to the service conditions
specified in UCI-3 and in accordance with UG-101(m)
shall be
(10) the pressure vessel or pressure vessel part meets
the standard hydrostatic test prescribed in UCI-99.
(b) Surface imperfections, such as undue roughness,
which do not permit leakage in cast iron materials may be
repaired using driven plugs provided:
(1) the vessel or vessel parts operate within the limits
of UCI-3(a)(1), (2), or (4);
(2) no welding is performed;
(3) the material from which the plug is manufactured
conforms in all respects to the material specification which
applies to the pressure vessel or pressure vessel part;
(4) the depth of the plug is not greater than 20% of
the thickness of the section and its diameter is not greater
PR p
PB
(specified minimum tensile strength)
ⴛ
6.67 (avg. tensile strength of test specimens)
where
PB p destruction test pressure
PR p maximum allowable working pressure at
operating temperatures listed in Table UCI-23
The principle of UG-101(c) shall be followed.
NOTE: It is assumed that failure will occur in bending.
221
2010 SECTION VIII — DIVISION 1
(b) The value of the average tensile strength of test
specimens in the foregoing equation shall be determined
from the test results of three test bars from the same ladle
of iron as used in the part, or from three test specimens
cut from the part.
MARKING AND REPORTS
UCI-115
GENERAL
The provisions for marking and reports in UG-115
through UG-120 shall apply without supplement to vessels
constructed of cast iron.
(c) All vessels or vessel parts of the same material,
design, and construction, whose maximum allowable working pressure is based on a test to destruction of a sample
vessel in accordance with (a) above, shall be considered
to have a design pressure equal to the maximum allowable
working pressure thus determined, except as limited by
the rules of UCI-3, and shall be subjected to a hydrostatic
test pressure in conformity with the rules of UCI-99.
PRESSURE RELIEF DEVICES
UCI-125
GENERAL
The provisions for pressure relief devices in UG-125
through UG-136 shall apply without supplement to vessels
constructed of cast iron.
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2010 SECTION VIII — DIVISION 1
PART UCL
REQUIREMENTS FOR WELDED PRESSURE VESSELS
CONSTRUCTED OF MATERIAL WITH CORROSION
RESISTANT INTEGRAL CLADDING, WELD METAL
OVERLAY CLADDING, OR WITH APPLIED LININGS
guidance regarding metallurgical phenomena in Appendix
A of Section II, Part D.
It is recommended that users assure themselves by appropriate tests, or otherwise, that the alloy material selected
and its heat treatment during fabrication will be suitable
for the intended service.
GENERAL
UCL-1
SCOPE
The rules in Part UCL are applicable to pressure vessels
or vessel parts that are constructed of base material with
corrosion resistant integral or weld metal overlay cladding
and to vessels and vessel parts that are fully or partially
lined inside or outside with corrosion resistant plate, sheet,
or strip, attached by welding to the base plates before or
after forming or to the shell, heads, and other parts during
or after assembly into the completed vessel.1 These rules
shall be used in conjunction with the general requirements
in Subsection A and with the specific requirements in the
applicable Parts of Subsection B.
UCL-2
NOTE: Attention is called to the difficulties that have been experienced
in welding materials differing greatly in chemical composition. Mixtures
of uncertain chemical composition and physical properties are produced
at the line of fusion. Some of these mixtures are brittle and may give rise
to cracks during solidification or afterward. To avoid weld embrittlement,
special care is required in the selection of lining material and welding
electrodes, and in the application of controls over the welding process
and other fabrication procedures.
MATERIALS
METHODS OF FABRICATION
UCL-10
Vessels and vessel parts of base material with corrosion
resistant integral or weld metal overlay cladding construction shall be fabricated by welding. Corrosion resistant
linings may be attached by welding to vessels fabricated
by any method of construction permitted under the rules
of this section.
The base materials used in the construction of clad vessels and of those having applied corrosion linings shall
comply with the requirements for materials given in
UCS-5, UF-5, UHT-5, or ULW-5.
UCL-11
UCL-3
CONDITIONS OF SERVICE
INTEGRAL AND WELD METAL
OVERLAY CLAD MATERIAL
(a) Clad material used in constructions in which the
design calculations are based on the total thickness including cladding [see UCL-23(c)] shall conform to one of the
following specifications:
(1) SA-263, Stainless Chromium Steel-Clad Plate
(2) SA-264, Stainless Chromium–Nickel Steel-Clad
Plate
(3) SA-265, Nickel and Nickel-Base Alloy-Clad
Steel Plate
In addition to the above, weld metal overlay cladding
may be used as defined in this Part.
Specific chemical compositions, heat treatment procedures, fabrication requirements, and supplementary tests
may be required to assure that the vessel will be suitable
for the intended service. This is particularly true for vessels
subject to severe corrosive conditions, and also those vessels operating in a cyclic temperature service. These rules
do not indicate the selection of an alloy suitable for the
intended service or the amount of the corrosion allowance
to be provided. See also informative and nonmandatory
1
GENERAL
See 3-2, Definition of Terms.
223
2010 SECTION VIII — DIVISION 1
(b) Base material with corrosion resistant integral or
weld metal overlay cladding used in constructions in which
the design calculations are based on the base material thickness, exclusive of the thickness of the cladding material,
may consist of any base material satisfying the requirements of UCL-10 and any metallic corrosion resistant integral or weld metal overlay cladding material of weldable
quality that in the judgment of the user is suitable for the
intended service.
(c) Base material with corrosion resistant integral cladding in which any part of the cladding is included in the
design calculations, as permitted in UCL-23(c), shall show
a minimum shear strength of 20,000 psi (140 MPa) when
tested in the manner described in the clad plate specification. One shear test shall be made on each such clad plate
as rolled, and the results shall be reported on the material
test report.
When the composite thickness of the clad material is
3
⁄4 in. (19 mm) or less, and /or when the cladding metal
thickness is nominally 0.075 in. (1.9 mm) or less, the
“Bond Strength” test, as described in SA-263, SA-264, or
SA-265, may be used in lieu of the bond “Shear Strength”
test to fulfill the criteria for acceptable minimum shear
strength, except that the bend test specimen shall be 11⁄2 in.
(38 mm) wide by not more than 3⁄4 in. (19 mm) in thickness
and shall be bent, at room temperature, through an angle
of 180 deg to the bend diameter provided for in the material
specifications applicable to the backing metal. The results
of the “Bond Strength” test shall be reported on the certified
material test report.
(d) A shear or bond strength test is not required for
weld metal overlay cladding.
(e) When any part of the cladding thickness is specified
as an allowance for corrosion, such added thickness shall
be removed before mill tension tests are made. When corrosion of the cladding is not expected, no part of the cladding
need be removed before testing, even though excess thickness seems to have been provided or is available as corrosion allowance.
UCL-12
overlay cladding and those having applied corrosion resistant linings and shall be used in conjunction with the general requirements for Design in Subsection A, and with
the specific requirements for Design in Subsection B that
pertain to the method of fabrication used.
(b) Minimum Thickness of Shells and Heads. The minimum thickness specified in UG-16(b) shall be the total
thickness for clad material with corrosion resistant integral
or weld metal overlay cladding and the base-material thickness for applied-lining construction.
UCL-23
(a) Applied Corrosion Resistant Linings. The thickness
of material used for applied lining shall not be included
in the computation for the required thickness of any lined
vessel. The maximum allowable stress value shall be that
given for the base material in Table UCS-23, or UNF-23.
(b) Integrally Clad Material Without Credit for Full
Cladding Thickness. Except as permitted in (c) below,
design calculations shall be based on the total thickness
of the clad material less the specified nominal minimum
thickness of cladding. A reasonable excess thickness either
of the actual cladding or of the same thickness of corrosion
resistant weld metal may be included in the design calculations as an equal thickness of base material. The maximum
allowable stress value shall be that given for the base
material referenced in Table UCS-23, UF-6, or UHT-23
and listed in Table 1A of Section II, Part D.
(c) Base Material with Corrosion Resistant Integral or
Weld Metal Overlay Cladding With Credit for Cladding
Thickness. When the base material with corrosion resistant
integral cladding conforms to one of the specifications
listed in UCL-11(a), or consists of an acceptable base
material with corrosion resistant weld metal overlay and
the joints are completed by depositing corrosion resisting
weld metal over the weld in the base material to restore
the cladding, the design calculations may be based on a
thickness equal to the nominal thickness of the base material plus Sc /Sb times the nominal thickness of the cladding
after any allowance provided for corrosion has been
deducted, where
LINING
Material used for applied corrosion resistant lining may
be any metallic material of weldable quality that in the
judgment of the user is suitable for the intended purpose.
Sb p maximum allowable stress value for the base
material at the design temperature
Sc p maximum allowable stress value for the integral
cladding at the design temperature, or for corrosion resistant weld metal overlay cladding, that
of the wrought material whose chemistry most
closely approximates that of the cladding, at the
design temperature
DESIGN
UCL-20
MAXIMUM ALLOWABLE STRESS
VALUES
GENERAL
(a) The rules in the following paragraphs apply specifically to pressure vessels and vessel parts constructed of
base material with corrosion resistant integral or weld metal
Where Sc is greater than Sb, the multiplier Sc /Sb shall
be taken equal to unity. The maximum allowable stress
224
2010 SECTION VIII — DIVISION 1
value shall be that given for the base material referenced
in Table UCS-23, UF-6, or UHT-23 and listed in Table
1A of Section II, Part D. Vessels in which the cladding is
included in the computation of required thickness shall not
be constructed for internal pressure under the provisions
of Table UW-12, column (c).
The thickness of the corrosion resistant weld metal overlay cladding deposited by manual processes shall be verified by electrical or mechanical means. One examination
shall be made for every head, shell course, or any other
pressure retaining component for each welding process
used. The location of examinations shall be chosen by the
Inspector except that, when the Inspector has been duly
notified in advance and cannot be present or otherwise
make the selection, the fabricator may exercise his own
judgment in selecting the locations.
UCL-26
THICKNESS OF SHELLS AND
HEADS UNDER EXTERNAL
PRESSURE
The thickness of shells or heads under external pressure
shall satisfy the requirements of the Part of Subsection C
applicable to the base material. The cladding may be
included in the design calculations for clad material to the
extent provided in UCL-23(b) and (c).
UCL-27
LOW TEMPERATURE OPERATIONS
The base materials used in the construction of vessels
shall satisfy the requirements of UCS-66, UCS-67,
UCS-68, Part UF, or UHT-5.
FABRICATION
UCL-30
UCL-24
MAXIMUM ALLOWABLE WORKING
TEMPERATURE
The rules in the following paragraphs apply specifically
to pressure vessels and vessel parts constructed of base
material with corrosion resistant integral or weld metal
overlay cladding and those having applied corrosion resistant linings, and shall be used in conjunction with the
general requirements for Fabrication in Subsection A, and
with the specific requirements for Fabrication in Subsection B that pertain to the method of fabrication used.
(a) When the design calculations are based on the thickness of base material exclusive of lining or cladding thickness, the maximum service metal temperature of the vessel
shall be that allowed for the base material.
(b) When the design calculations are based on the full
thickness of base material with corrosion resistant integral
or weld metal overlay cladding as permitted in UCL-23(c),
the maximum service metal temperature shall be the lower
of the values allowed for the base material referenced in
Table UCS-23, UF-6, or UHT-23 and listed in Table 1A
of Section II, Part D, or refer to UCL-23(c) for corrosion
resistant weld metal overlay cladding and the cladding
material referenced in Table UHA-23 or UNF-23.
(c) The use of corrosion resistant integral or weld metal
overlay cladding or lining material of chromium-alloy
stainless steel with a chromium content of over 14% is not
recommended for service metal temperatures above 800°F
(425°C).
UCL-25
GENERAL
UCL-31
JOINTS IN INTEGRAL OR WELD
METAL OVERLAY CLADDING AND
APPLIED LININGS
(a) The types of joints and welding procedure used shall
be such as to minimize the formation of brittle weld composition by the mixture of metals of corrosion resistant alloy
and the base material.
(b) When a shell, head, or other pressure part is welded
to form a corner joint, as in Fig. UW-13.2, the weld shall
be made between the base materials either by removing
the clad material prior to welding the joint or by using
weld procedures that will assure the base materials are
fused. The corrosion resistance of the joint may be provided
by using corrosion resistant and compatible weld filler
material or may be restored by any other appropriate means.
CORROSION OF CLADDING OR
LINING MATERIAL
NOTE: Because of the different thermal coefficients of expansion of
dissimilar metals, caution should be exercised in design and construction
under the provisions of these paragraphs in order to avoid difficulties in
service under extreme temperature conditions, or with unusual restraint
of parts such as may occur at points of stress concentration.
(a) When corrosion or erosion of the cladding or lining
material is expected, the cladding or lining thickness shall
be increased by an amount that in the judgment of the user
will provide the desired service life.
(b) Telltale Holes. The requirements of UG-25(e) and
UG-46(b) shall apply when telltale holes are used in clad
or lined vessels, except that such holes may extend to the
cladding or lining.
UCL-32
WELD METAL COMPOSITION
Welds that are exposed to the corrosive action of the
contents of the vessel should have a resistance to corrosion
225
2010 SECTION VIII — DIVISION 1
that is not substantially less than that of the corrosion
resistant integral or weld metal overlay cladding or lining.
The use of filler metal that will deposit weld metal with
practically the same composition as the material joined is
recommended. Weld metal of different composition may
be used provided it has better mechanical properties in the
opinion of the manufacturer, and the user is satisfied that
its resistance to corrosion is satisfactory for the intended
service. The columbium content of columbium-stabilized
austenitic stainless steel weld metal shall not exceed 1.00%,
except when a higher columbium content is permitted in
the material being welded.
UCL-33
overlay cladding and those having applied corrosion resistant linings shall be radiographed when required by the
rules in UW-11, UCS-57, UHT-57, and UCL-36. The material thickness specified under these rules shall be the total
material thickness for clad construction and the base material thickness for applied-lining construction, except as
provided in (c) below.
(b) Base Material Weld Protected by a Strip Covering.
When the base material weld in clad or lined construction is
protected by a covering strip or sheet of corrosion resistant
material applied over the weld in the base material to
complete the cladding or lining, any radiographic examination required by the rules of UW-11, UHT-57, and UCS-57
may be made on the completed weld in the base material
before the covering is attached.
(c) Base Material Weld Protected by an Alloy Weld. The
radiographic examination required by the rules in UW-11,
UHT-57, and UCS-57 shall be made after the joint, including the corrosion resistant layer, is complete, except that
the radiographic examination may be made on the weld in
the base material before the alloy cover weld is deposited,
provided the following requirements are met.
(1) The thickness of the base material at the welded
joint is not less than required by the design calculation.
(2) The corrosion resistant alloy weld deposit is nonair-hardening.
(3) The completed alloy weld deposit is spot examined by any method that will detect cracks.
(4) The thickness of the base material shall be used
in determining the radiography requirement in (a) above.
INSERTED STRIPS IN CLAD
MATERIAL
The thickness of inserted strips used to restore cladding
at joints shall be equal to that of the nominal minimum
thickness of cladding specified for the material backed, if
necessary, with corrosion resistant weld metal deposited
in the groove to bring the insert flush with the surface of
the adjacent cladding.
UCL-34
POSTWELD HEAT TREATMENT
CAUTION: Postweld heat treatment may be in the carbide-precipitation
range for unstabilized austenitic chromium–nickel steels, as well as within
the range where a sigma phase may form, and if used indiscriminately
could result in material of inferior physical properties and inferior corrosion resistance, which ultimately could result in failure of the vessel.
(a) Vessels or parts of vessels constructed of base material with corrosion resistant integral or weld metal overlay
cladding or applied corrosion resistant lining material shall
be postweld heat treated when the base material is required
to be postweld heat treated. In applying these rules, the
determining thickness shall be the thickness of the base
material.
When the thickness of the base material requires postweld heat treatment, it shall be performed after the application of corrosion resistant weld metal overlay cladding or
applied corrosion resistant lining unless exempted by the
Notes of Table UCS-56.
(b) Vessels or parts of vessels constructed of chromium
stainless steel integral or weld metal overlay cladding and
those lined with chromium stainless steel applied linings
shall be postweld heat treated in all thicknesses, except
vessels that are integrally clad or lined with Type 405 or
Type 410S and welded with an austenitic electrode or nonair-hardening nickel–chromium–iron electrode need not be
postweld heat treated unless required by (a) above.
UCL-35
UCL-36
EXAMINATION OF CHROMIUM
STAINLESS STEEL CLADDING OR
LINING
The alloy weld joints between the edges of adjacent
chromium stainless steel cladding layers or liner sheets
shall be examined for cracks as follows.
(a) Joints welded with straight chromium stainless steel
filler metal shall be examined throughout their full length.
The examination shall be by radiographic methods when
the chromium stainless steel welds are in continuous contact with the welds in the base metal. Liner welds that are
attached to the base metal, but merely cross the seams in
the base metal, may be examined by any method that will
disclose surface cracks.
(b) Joints welded with austenitic chromium–nickel steel
filler metal or non-air-hardening nickel–chromium–iron
filler metal shall be given a radiographic spot examination
in accordance with UW-52. For lined construction, at least
one spot examination shall include a portion of the liner
weld that contacts weld metal in the base material.
RADIOGRAPHIC EXAMINATION
(a) General. Vessels or parts of vessels constructed of
base material with corrosion resistant integral or weld metal
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2010 SECTION VIII — DIVISION 1
UCL-40
WELDING PROCEDURES
between the user and the manufacturer. The test should be
such as to assure freedom from damage to the load carrying
base material. When rapid corrosion of the base material
is to be expected from contact with the contents of the
vessel, particular care should be taken in devising and
executing the tightness test.
Following the hydrostatic pressure test, the interior of
the vessel shall be inspected to determine if there is any
seepage of the test fluid through the lining. Seepage of
the test fluid behind the applied lining may cause serious
damage to the liner when the vessel is put in service. When
seepage occurs, F-4 of Appendix F shall be considered
and the lining shall be repaired by welding. Repetition of
the radiography, and heat treatment, or the hydrostatic test
of the vessel after lining repairs is not required except
when there is reason to suspect that the repair welds may
have defects that penetrate into the base material, in which
case the Inspector shall decide which one or more shall
be repeated.
Welding procedures for corrosion resistant weld overlay,
composite (clad) metals, and attachment of applied linings
shall be prepared and qualified in accordance with the
requirements of Section IX.
UCL-42
ALLOY WELDS IN BASE METAL
Groove joints in base material and parts may be made
with corrosion resistant alloy-steel filler metal, or groove
joints may be made between corrosion resistant alloy steel
and carbon or low alloy steel, provided the welding procedure and the welders have been qualified in accordance
with the requirements of Section IX for the combination
of materials used. Some applications of this rule are base
metal welded with alloy-steel electrodes, and alloy nozzles
welded to steel shells.
UCL-46
FILLET WELDS
UCL-52
Fillet welds of corrosion resistant metal deposited in
contact with two materials of dissimilar composition may
be used for shell joints under the limitations of UW-12,
for connection attachments under the limitations of UW-15
and UW-16, and for any other uses permitted by this Division. The qualification of the welding procedures and welders to be used on fillet welds for a given combination of
materials and alloy weld metal shall be made in accordance
with the rules prescribed in Section IX.
The requirements for standard hydrostatic test in UG-99
shall apply to pressure vessels fabricated in accordance
with the rules of Part UCL.
MARKING AND REPORTS
UCL-55
GENERAL
The rules in the following paragraphs apply specifically
to the inspection and testing of pressure vessels and vessel
parts constructed of base material with corrosion resistant
integral or weld metal overlay cladding and those having
applied corrosion resistant linings, and shall be used in
conjunction with the general requirements for Inspection
and Tests in Subsection A, and with the specific requirements for Inspection and Tests in Subsection B that pertain
to the method of fabrication used.
PRESSURE RELIEF DEVICES
UCL-60
UCL-51
GENERAL
The provisions for marking and reports in UG-115
through UG-120 shall apply to vessels that are constructed
of base material with corrosion resistant integral or weld
metal overlay cladding and those having applied corrosion
resistant linings, with the following supplements to the
Data Reports.
(a) Include specification and type of lining material.
(b) Include applicable paragraph in UCL-23 under
which the shell and heads were designed.
INSPECTION AND TESTS
UCL-50
HYDROSTATIC TEST
GENERAL
The provisions for pressure relief devices given in
UG-125 through UG-136 shall apply without supplement
to welded vessels that are constructed of base material with
corrosion resistant integral or weld metal overlay cladding
and those having applied corrosion resistant linings.
TIGHTNESS OF APPLIED LINING
A test for tightness of the applied lining that will be
appropriate for the intended service is recommended, but
the details of the test shall be a matter for agreement
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2010 SECTION VIII — DIVISION 1
PART UCD
REQUIREMENTS FOR PRESSURE VESSELS
CONSTRUCTED OF CAST DUCTILE IRON
NOTE: Cast ductile iron flanges and fittings conforming in dimension
to the Class 125 and 250 American National Standard for cast iron flanges
and fittings may be used in whole or as a part of a pressure vessel at the
pressure–temperature ratings listed in ASME B16.42, except that NPS
31⁄2 and smaller screwed and tapped flanges conforming in dimensions
to the Class 125 ASME B16.1 for cast iron flanged fittings shall have
identical ratings specified in ASME B16.1.
GENERAL
UCD-1
SCOPE
The rules in Part UCD are applicable to pressure vessels
and pressure vessel parts that are constructed of cast ductile
iron,1 and shall be used in conjunction with the general
requirements in Subsection A insofar as these requirements
are applicable to cast material.
UCD-2
(c) Cast ductile iron flanges and fittings, Class 400 and
higher, conforming in dimension to the carbon steel pipe
flanges and flanged fittings in ASME B16.5 may be used
in whole or as a part of a pressure vessel at the pressure–
temperature ratings for carbon steel, material category 1.4,
in that standard provided the temperature is not less than
−20°F (−29°C) nor greater than 650°F (345°C) and provided that the pressure does not exceed 1,000 psi (7 MPa).
SERVICE RESTRICTIONS
Cast ductile iron pressure vessels shall not be used for
services as follows:
(a) to contain lethal 2 substances, either liquid or
gaseous;
(b) for unfired steam boilers as defined in U-1(g);
(c) for direct firing [see UW-2(d)].
MATERIALS
UCD-5
UCD-3
PRESSURE–TEMPERATURE
LIMITATIONS
GENERAL
All cast ductile iron material subject to stress due to
pressure shall conform to the specifications given in Section
II and shall be limited to those listed in Table UCD-23
except as otherwise provided in UG-11.
(a) The maximum design temperature shall not be
higher than 650°F (345°C). The minimum design temperature shall not be less than −20°F (−29°C), and the design
pressure shall not exceed 1,000 psi (7 MPa) unless the
requirements in UG-24 for a casting quality factor of 90%
are met, and the vessel contains liquids only.
(b) Cast ductile iron flanges and fittings covered by
ASME B16.42 may be used in whole or as a part of a
pressure vessel at the pressure–temperature ratings listed
in that standard.
UCD-12
BOLT MATERIALS
The requirements for bolt materials, nuts, and washers
shall be the same as for carbon and low alloy steels in
UCS-10 and UCS-11.
DESIGN
1
It is the intent that cast ductile irons with an elongation of less than
15% in 2 in. (50 mm) be treated as cast iron and that vessels or pressure
parts of such material be designed and fabricated in accordance with the
rules in Part UCI.
2
By lethal substances are meant poisonous gases or liquids of such
a nature that a very small amount of the gas or of the vapor of the liquid
mixed or unmixed with air is dangerous to life when inhaled. For purposes
of this Division, this class includes substances of this nature which are
stored under pressure or may generate a pressure if stored in a closed
vessel.
UCD-16
GENERAL
The rules in the following paragraphs apply specifically
to the design of pressure vessels and pressure vessel parts
of cast ductile iron and shall be used in conjunction with
the general requirements for Design in Subsection A insofar
as these requirements are applicable to cast materials.
228
2010 SECTION VIII — DIVISION 1
TABLE UCD-23
MAXIMUM ALLOWABLE STRESS VALUES IN TENSION
FOR CAST DUCTILE IRON, ksi (MPa)
Spec.
No.
Class
Note
Specified
Min.
Tensile
Strength
[Note (1)]
SA-395
...
(1)
60 (414)
For Metal
Temp., °F
(°C) Not
Exceeding
−20 (−29)
to 650
(345)
Ext.
Pressure
Chart Fig.
No.
[Note (2)]
12.0 (82.7)
CD-1
UCD-35
(a) Circular cast ductile iron spherically shaped heads
with bolting flanges, similar to Fig. 1-6 sketches (b), (c),
and (d) shall be designed in accordance with the provisions
in 1-6, except that corners and fillets shall comply with
the requirements of UCD-37.
(b) Circular cast ductile iron spherically shaped heads
with bolting flanges other than those described in (a) above
shall be designed in accordance with the following requirements.
(1) The head thickness shall be determined in accordance with the requirements in UG-32.
(2) The spherical and knuckle radii shall conform to
the requirements in UG-32.
(3) Flanges made of cast ductile iron in compliance
with SA-395 and conforming in dimensions to American
National Standard for carbon steel given in ASME B16.5
may be used at pressures not exceeding 80% of the pressures permitted in those standards at their listed temperatures provided the temperature is not less than −20°F
(−29°C) nor greater than 650°F (345°C) and provided that
the adjusted service pressure does not exceed 1,000 psi
(7 MPa).
GENERAL NOTE: To these stress values, a quality factor as specified
in UG-24 shall be applied.
NOTES:
(1) The yield stresses in compression and tension for cast ductile iron
are not sufficiently different to justify an increase in the allowable
stress for bending except as permitted in 2-8(a).
(2) Refer to Subpart 3 of Section II, Part D.
For components for which the Code provides no design
rules, the provisions of UG-19(b) and (c) apply. If a proof
test is performed, the rules of UCD-101 apply.
UCD-23
MAXIMUM ALLOWABLE STRESS
VALUES
Table UCD-23 gives the maximum allowable stress values at the temperatures indicated for castings conforming
to the Specification listed therein. These stress values shall
be limited to the stress values in Table UCD-23 multiplied
by the applicable casting quality factor given in UG-24.
UCD-28
NOTE: Cast ductile iron flanges conforming in dimension to the 125
and 250 lb American National Standard for cast iron flanges may be used
for pressures not exceeding 80% of the American National Standard
pressure ratings for 150 lb and 300 lb carbon steel flanges, respectively,
at their listed temperatures provided the temperature is not less than
−20°F (−29°C) nor greater than 650°F (345°C), except as in Note to
UCD-3(b).
THICKNESS OF SHELLS UNDER
EXTERNAL PRESSURE
UCD-36
(a) Cylindrical and spherical shells under external pressure shall be designed by the rules in UG-28, using the
applicable figures in Subpart 3 of Section II, Part D and
the temperature limits of UG-20(c).
(b) Examples illustrating the use of charts in the figures
for the design of vessels under external pressure are given
in Appendix L.
UCD-32
OPENINGS AND REINFORCEMENTS
(a) The dimensional requirements in UG-36 through
UG-46 are applicable to cast ductile iron and shall be used
in the design of openings and reinforcements in pressure
vessels and pressure vessel parts which are cast integrally
with the vessel or vessel part. In no case shall the thickness
of the reinforcement, including the nominal thickness of
the vessel wall, exceed twice the nominal thickness of the
vessel wall.
(b) Cast ductile iron flanges, nozzles, and openings shall
not be attached to steel or nonferrous pressure vessels or
pressure parts by welding or brazing, nor shall they be
considered to contribute strength to the vessel or part.
HEADS WITH PRESSURE ON
CONCAVE SIDE
Heads with pressure on the concave side (plus heads)
shall be designed in accordance with the formulas in
UG-32.
UCD-33
SPHERICALLY SHAPED COVERS
(HEADS)
HEADS WITH PRESSURE ON
CONVEX SIDE
UCD-37
CORNERS AND FILLETS
A liberal radius shall be provided at projecting edges
and in reentrant corners in accordance with good foundry
practice. Abrupt changes in surface contour and in wall
The thickness of heads with pressure on the convex side
(minus heads) shall not be less than the thickness required
in UG-33.
229
2010 SECTION VIII — DIVISION 1
TABLE UCD-78.1
TABLE UCD-78.2
Minimum Thickness
of Repaired
Section, in. (mm)
NPS Plug or
Equivalent
1
⁄8
⁄4
3
⁄8
1
⁄2
3
⁄4
11
1
7
⁄32
⁄16
1
⁄2
21
⁄32
3
⁄4
(9)
(11)
(13)
(17)
(19)
1
11⁄4
11⁄2
2
13
(21)
(22)
(24)
(25)
⁄16
7
⁄8
15
⁄16
1
NPS Plug or
Equivalent
1
2
1
11⁄4
11⁄2
2
21⁄2
4
51⁄4
81⁄8
(14)
(17)
(27)
(32)
(50)
(64)
(100)
(134)
(207)
excess wall thickness in terms of plug diameter and coincident thread engagement, other types of plugs may be used
provided both full thread engagement and effective sealing
against pressure are obtained. Where possible, the ends of
the plug should be ground smooth after installation to
conform to the inside and outside contours of the walls of
the pressure vessel or pressure part;
(5) the material from which the plug is manufactured
shall conform in all respects to the material specification
which applies to the pressure vessel or pressure vessel part;
(6) the machined surface of the drilled or bored hole
before tapping shall be free from visible defects and the
adjacent metal shown to be sound by radiographic examination;
(7) the thickness of any repaired section in relation
to the size of plug used shall not be less than that given
in Table UCD-78.1;
(8) the minimum radius of curvature of repaired sections of cylinders or cones in relation to the size of plug
used shall not be less than that given in Table UCD-78.2;
(9) the ligament efficiency between any two adjacent
plugs shall not be less than 80% where
FABRICATION
GENERAL
The rules in the following paragraphs apply specifically
to the fabrication of pressure vessels and pressure vessel
parts of cast ductile iron and shall be used in conjunction
with the general requirements for Fabrication in Subsection A insofar as these requirements are applicable to cast
materials.
UCD-78
9
⁄16
11
⁄16
11⁄16
11⁄4
⁄8
⁄4
3
⁄8
1
⁄2
3
⁄4
1
thickness at junctures shall be avoided. Fillets shall conform to the following:
(a) Fillets forming the transition between the pressure
containing walls and integral attachments, such as brackets,
lugs, supports, nozzles, flanges, and bosses, shall have a
radius not less than one-half the thickness of the pressure
containing wall adjacent to the attachment.
UCD-75
Minimum Radius
of Curvature of
Cylinder or Cone,
in. (mm)
REPAIRS IN CAST DUCTILE IRON
MATERIAL
(a) Imperfections which permit leakage in cast ductile
iron materials may be repaired by using threaded plugs
provided:
(1) the vessel or vessel parts operate within the temperature limits of UCD-3(a), and the design pressure does
not exceed 1,000 psi (7 MPa);
(2) no welding is performed;
(3) the diameter of the plug shall not exceed the diameter of a standard NPS 2 pipe plug;
(4) the plugs, where practical, shall conform in all
dimensions to standard NPS pipe plugs, and in addition
they shall have full thread engagement corresponding to
the thickness of the repaired section. (See Table UCD78.1.) Where a tapered plug is impractical because of
p−
Ep
冢
d1 + d 2
2
冣
p
and
d1, d2 p respective diameters of the two plugs under
consideration
E p ligament efficiency
p p distance between plug centers
(10) the pressure vessel or pressure vessel part meets
the standard hydrostatic test prescribed in UCD-99.
(b) Surface imperfections, such as undue roughness,
which do not permit leakage in cast ductile iron materials
may be repaired using driven plugs provided:
230
2010 SECTION VIII — DIVISION 1
(1) the vessel or vessel parts are to operate within
the limits of UCD-3(a);
(2) no welding is performed;
(3) the material from which the plug is manufactured
shall conform in all respects to the material specification
which applies to the pressure vessel or pressure vessel part;
(4) the depth of the plug is not greater than 20% of
the thickness of the section and its diameter is not greater
than its engaged length;
(5) the pressure vessel or pressure vessel part meets
the standard hydrostatic test prescribed in UCD-99.
where
f p casting quality factor as defined in UG-24, which
applies only to identical cast ductile iron vessels
put into service
PB p destruction test pressure
PR p maximum allowable working pressure of identical
cast ductile iron vessels
The principle of UG-101(c) shall be followed.
(b) The value of the average tensile strength of test
specimens in the foregoing equation shall be determined
from the test results of three test bars from the same ladle
of iron as used in the part, or from three test specimens
cut from the part.
(c) All pressure vessels or pressure vessel parts of the
same material, design, and construction, whose maximum
allowable working pressure is based on the destruction test
of a sample vessel or part, shall be subjected to a hydrostatic
test pressure of not less than twice the maximum allowable
working pressure determined by the application of the rules
in (a).
INSPECTION AND TESTS
UCD-90
GENERAL
The rules in the following paragraphs apply specifically
to the inspection and testing of pressure vessels and pressure vessel parts of cast ductile iron and shall be used in
conjunction with the general requirements of Inspection
and Tests in Subsection A insofar as these requirements
are applicable to cast material.
UCD-99
STANDARD HYDROSTATIC TEST
MARKING AND REPORTS
Cast ductile iron pressure vessels and pressure vessel
parts shall be hydrostatically tested by the method prescribed in UG-99 except that the test pressure shall be two
times the maximum allowable working pressure.
UCD-101
UCD-115
GENERAL
The provisions for marking and preparing reports in
UG-115 through UG-120 shall apply without supplement
to vessels constructed of cast ductile iron.
HYDROSTATIC TEST TO
DESTRUCTION
(a) The maximum allowable working pressure of identical cast ductile iron vessels, based on testing one of them
to destruction in accordance with UG-101(m), shall be
UCD-125
specified min.
tensile strength
avg. tensile strength of
test specimens
冢 冣冢
P f
PR p B
5
PRESSURE RELIEF DEVICES
冣
GENERAL
The provisions for the application of pressure relief
devices in UG-125 through UG-136 shall apply without
supplement to vessels constructed of cast ductile iron.
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2010 SECTION VIII — DIVISION 1
PART UHT
REQUIREMENTS FOR PRESSURE VESSELS
CONSTRUCTED OF FERRITIC STEELS
WITH TENSILE PROPERTIES
ENHANCED BY HEAT TREATMENT
(c) All steels listed in Table UHT-23 shall be tested for
notch ductility, as required by UHT-6. These tests shall be
conducted at a temperature not warmer than the minimum
design metal temperature (see UG-20) but not warmer than
+32°F (0°C). Materials may be used at temperatures colder
than the minimum design metal temperature as limited in
(1) and (2) below.
(1) When the coincident ratio defined in Fig.
UCS-66.1 is 0.35 or less, the corresponding minimum
design metal temperature shall not be colder than −155°F
(−104°C).
(2) When the coincident ratio defined in Fig.
UCS-66.1 is greater than 0.35, the corresponding minimum
design metal temperature shall not be colder than the impact
test temperature less the allowable temperature reduction
permitted in Fig. UCS-66.1 and shall in no case be colder
than −155°F (−104°C).
(d) All test specimens shall be prepared from the material in its final heat treated condition or from full-thickness
samples of the same heat similarly and simultaneously
treated. Test samples shall be of such size that the prepared
test specimens are free from any change in properties due
to edge effects. When the material is clad or weld deposit
overlayed by the producer or fabricator prior to quench
and temper treatments, the full thickness samples shall be
clad or weld deposit overlayed before such heat treatments.
(e) Where the vessel or vessel parts are to be hot formed
or postweld heat treated (stress relieved), this identical heat
treatment shall be applied to the test specimens required
by the material specifications including the cooling rate
specified by the fabricator which shall in no case be slower
than that specified in the applicable material specification.
(f) All material shall be heat treated in accordance with
the applicable material specifications.
GENERAL
UHT-1
SCOPE
The rules in Part UHT are applicable to pressure vessels
and vessel parts that are constructed of ferritic steels suitable for welding, whose tensile properties have been
enhanced by heat treatment, and shall be used in conjunction with the general requirements in Subsection A, and
with the specific requirements in Part UW of Subsection
B. The heat treatment may be applied to the individual
parts of a vessel prior to assembly by welding, to partially
fabricated components, or to an entire vessel after completion of welding. This part is not intended to apply to those
steels approved for use under the rules of Part UCS but
which are furnished in such thicknesses that heat treatment
involving the use of accelerated cooling, including liquid
quenching, is used to attain structures comparable to those
attained by normalizing thinner sections. Integrally forged
vessels, quenched and tempered, which do not contain
welded seams, are not intended to be covered by the rules
of this Part.
MATERIALS
UHT-5
GENERAL
(a) Steels covered by this Part subject to stress due to
pressure shall conform to one of the specifications given
in Section II and shall be limited to those listed in Table
UHT-23.
The thickness limitations of the material specifications
shall not be exceeded.
(b) Except when specifically prohibited by this Part
[such as in UHT-18 and UHT-28], steels listed in Table
UHT-23 may be used for the entire vessel or for individual
components which are joined to other Grades listed in that
Table or to other steels conforming to specifications listed
in Parts UCS or UHA of this Division.
UHT-6
TEST REQUIREMENTS
(a)(1) One Charpy V-notch test (three specimens) shall
be made from each plate as heat treated, and from each
232
(10)
2010 SECTION VIII — DIVISION 1
FIG. UHT-6.1 CHARPY V-NOTCH IMPACT TEST
REQUIREMENTS
FIG. UHT-6.1M CHARPY V-NOTCH IMPACT TEST
REQUIREMENTS
1.0
40
0.9
Cv, Lateral Expansion, mm
Cv, Lateral Expansion, mils
0.8
30
20
10
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
0
1.0
2.0
3.0
0
4.0
Maximum Nominal Thickness, in.
10
20
30
40
50
60
70
80
90
100
Maximum Nominal Thickness, mm
GENERAL NOTE: For Table UCS-23 materials having a specified
minimum tensile strength of 95,000 psi or greater, and for
Table UHT-23 materials.
GENERAL NOTE: For Table UCS-23 materials having a specified
minimum tensile strength of 655 MPa or greater, and for Table UHT23 materials.
heat of bars, pipe, tube, rolled sections, forged parts, or
castings included in any one heat treatment lot.
(2) The test procedures, and size, location and orientation of the specimens shall be the same as required by
UG-84 except that for plates the specimens shall be oriented transverse to the final direction of rolling and for
circular forgings the specimens shall be oriented tangential
to the circumference.
(3) Each of the three specimens tested shall have
a lateral expansion opposite the notch not less than the
requirements shown in Fig. UHT-6.1.
(4) If the value of lateral expansion for one specimen
is less than that required in Fig. UHT-6.1 but not less
than 2⁄3 of the required value, a retest of three additional
specimens may be made, each of which must be equal to
or greater than the required value in Fig. UHT-6.1. Such
a retest shall be permitted only when the average value of
the three specimens is equal to or greater than the required
value in Fig. UHT-6.1. If the values required are not
obtained in the retest or if the values in the initial test are
less than the values required for retest, the material may
be reheat treated. After reheat treatment, a set of three
specimens shall be made, each of which must be equal to
or greater than the required value in Fig. UHT-6.1.
(b) Materials conforming to SA-353 and SA-553 for
use at minimum design metal temperatures colder than
−320°F (−196°C), materials conforming to SA-508,
SA-517, SA-543, and SA-592 for use at minimum design
metal temperatures colder than −20°F (−29°C), and materials conforming to SA-645, Grade A, for use at minimum
design metal temperatures colder than −275°F (−171°C)
shall have, in addition to the Charpy tests required under
UHT-6(a), drop-weight tests as defined by ASTM E 208,
made as follows:
(1) For plates 5⁄8 in. (16 mm) thick and over, one dropweight test (two specimens) shall be made for each plate
as heat treated.
(2) For forgings and castings of all thicknesses, one
drop-weight test (two specimens) shall be made for each
heat in any one heat treatment lot using the procedure in
SA-350 for forgings and in SA-352 for castings.
(3) Each of the two test specimens shall meet the
“no-break” criterion, as defined by ASTM E 208, at test
temperature.
DESIGN
UHT-16
GENERAL
The rules in the following paragraphs apply specifically
to the design of pressure vessels and vessel parts that are
constructed of heat treated steels covered by this Part and
shall be used in conjunction with the general requirements
for Design in Subsection A and in Subsection B, Part UW.
UHT-17
WELDED JOINTS
(a) In vessels or vessel parts constructed of heat treated
steels covered by this Part except as permitted in (b) below,
all joints of Categories A, B, and C, as defined in UW-3,
and all other welded joints between parts of the pressure
233
(10)
2010 SECTION VIII — DIVISION 1
containing enclosure which are not defined by the category
designation, shall be in accordance with Type No. (1) of
Table UW-12. All joints of Category D shall be in accordance with Type No. (1) of Table UW-12 and Fig.
UHT-18.1 when the shell plate thickness is 2 in. (50 mm)
or less. When the thickness exceeds 2 in. (50 mm), the
weld detail may be as permitted for nozzles in Fig. UHT18.1 and Fig. UHT-18.2.
(b) For materials SA-333 Grade 8, SA-334 Grade 8,
SA-353, SA-522, SA-553, and SA-645, Grade A, the joints
of various categories (see UW-3) shall be as follows:
(1) All joints of Category A shall be Type No. (1)
of Table UW-12.
(2) All joints of Category B shall be Type No. (1) or
(2) of Table UW-12.
(3) All joints of Category C shall be full penetration
welds extending through the entire section at the joint.
(4) All joints of Category D attaching a nozzle neck
to the vessel wall and to a reinforcing pad, if used, shall
be full penetration groove welds.
(4) the diameter of the nozzle neck does not exceed
the limits given in 1-7 for openings designed to UG-36
through UG-44.
(c) Nozzles of nonhardenable austenitic-type stainless
steel may be used in vessels constructed of steels conforming to SA-353, SA-553 Types I and II, or SA-645, Grade
A, provided the construction meets all of the following
conditions:
(1) The nozzles are nonhardenable austenitic-type
stainless steel conforming to one of the following specifications: SA-182, SA-213, SA-240, SA-312, SA-336,
SA-403, SA-430, or SA-479.
(2) The maximum nozzle size is limited to NPS 4.
(3) None of the nozzles is located in a Category A
or B joint.
(4) The nozzles are located so that the reinforcement
area of one nozzle does not overlap the reinforcement area
of an adjacent nozzle.
UHT-19
(10)
UHT-18
CONICAL SECTIONS
Conical sections shall be provided with a skirt having
a length not less than 0.50冪rt (where r is the inside radius
of the adjacent cylinder and t is the thickness of the cone),
or 11⁄2 in. (38 mm) whichever is larger. A knuckle shall be
provided at both ends of the conical section; the knuckle
radius shall not be less than 10% of the outside diameter
of the skirt, but in no case less than three times the cone
thickness.
NOZZLES
(a) All openings regardless of size shall meet the
requirements for reinforcing, nozzle geometry, and nozzle
attachments and shall conform to details shown in Fig.
UHT-18.1 or as shown in Fig. UHT-18.2 or sketch (y-l)
or (z-l) in Fig. UW-16.1 when permitted by the provisions
of UHT-17(a), or as shown in Fig. UW-16.1 when permitted by the provisions of UHT-17(b).
(b) Except for nozzles covered in (c) below, all nozzles
and reinforcement pads shall be made of material with a
specified minimum yield strength within ±20% of that of
the shell to which they are attached; however, pipe flanges,
pipe, or communicating chambers may be of carbon, low,
or high alloy steel welded to nozzle necks of the required
material provided:
(1) the joint is a circumferential butt weld located
not less than 冪Rtn which, except for the nozzle type shown
in Fig. UHT-18.1 sketch (f), is measured from the limit of
reinforcement as defined in UG-40. For Fig. UHT-18.1
sketch (f), the 冪Rtn is measured as shown on that Figure.
In these equations,
UHT-20
JOINT ALIGNMENT
The requirements of UW-33 shall be met except that
the following maximum permissible offset values shall be
used in place of those given in UW-33(a):
Section Thickness,
in. (mm)
Up to 1⁄2 (13), incl.
Over 1⁄2 to 15⁄16
(13 to 24), incl.
⁄16 to 11⁄2
(24 to 38), incl.
Over 11⁄2 (38)
Over
R p inside radius of the nozzle neck except for Fig.
UHT-18.1 sketch (f) where it is the inside radius
of the vessel opening as shown in that Figure
tn p nominal thickness of the nozzle
15
Joint Direction
Longitudinal
0.2t
Circumferential
0.2t
3
⁄32 in. (2.5 mm) 0.2t
3
⁄32 in. (2.5 mm)
3
⁄32 in. (2.5 mm) Lesser of 1⁄8t
3
⁄16 in. (5 mm)
or 1⁄4 in. (6 mm)
UHT-23
(2) the design of the nozzle neck at the joint is made
on the basis of the allowable stress value of the weaker
material;
(3) the slope of the nozzle neck does not exceed three
to one for at least a distance of 1.5tn from the center of
the joint;
MAXIMUM ALLOWABLE STRESS
VALUES
(a) Table 1A of Section II, Part D gives the maximum
allowable stress values at the temperatures indicated for
materials conforming to the specifications listed therein.
Values may be interpolated for intermediate temperatures
234
2010 SECTION VIII — DIVISION 1
FIG. UHT-18.1 ACCEPTABLE WELDED NOZZLE ATTACHMENT READILY RADIOGRAPHED TO CODE STANDARDS
tn
tn
t
3
r2
1
r1
tn
r2
A
tn
45 deg max.
r2
18.5 deg max.
r2
Max.
r2
= 0.2t
30 deg min.
1/ in. (13 mm)
2
r2
r1
t3
t
r2
r
11/2 t min. 1
(b)
(a)
min.
r2
45 deg max.
30 deg max.
t
r2
tn
45 deg max.
r2
30 deg max.
r2
r2
r1
r1
1
t4
t
t
Section A–A
t3
2
t4
1
0.2t but
18.5 deg
2
30 deg
max.
Sections perpendicular
and parallel to the
cylindrical vessel axis
A
(c)
(c-1)
t
Backing ring
if used, shall
be removed
r2
tn
r2
r1
tn
r1
t
(d)
(e)
2R or (R t tn)
whichever is greater
R = inside radius of
vessel opening
Min. thickness (forging)
N
45 deg
r2
t (actual) shell C
N
r1
r2
t
tn
tp
=
=
=
=
21/2tn
1/ t to 1/ t
8
2
3/ in (19 mm)
4
nominal thickness of shell or head
nominal thickness of nozzle
nominal thickness of attached pipe
N
Rad. = 1/2tn with a min. = 1/4 in. (6 mm)
r1
2tn min.
r1
t
r1
r2
B
C
D
Rtn
Limits of reinforcement
A
45 deg
min.
(13 mm) min.
Limits of reinforcement
tp
1/ in.
2
Reinforcement may be distributed within the limits
prescribed by this Division
(f)
235
tn
Area to be
compensated
A, B, C, D
2010 SECTION VIII — DIVISION 1
FIG. UHT-18.2 ACCEPTABLE FULL PENETRATION WELDED NOZZLE ATTACHMENTS RADIOGRAPHABLE WITH
DIFFICULTY AND GENERALLY REQUIRING SPECIAL TECHNIQUES INCLUDING MULTIPLE EXPOSURES TO TAKE
CARE OF THICKNESS VARIATIONS
t
tn
tn
Backing strip
if used shall
be removed
tc
t
r1
tc
r1
(a)
(b)
tn
tn
Backing strip
if used shall
be removed
tc
r1
t
tc
r1
t
(c)
(d)
tn
tn
Backing strip
if used shall
be removed
tn min.
tc
r1
t
t
(e)
r1
tc
A
(f)
r2
tn
tn
r
tc 2
r4
r4
r1
tc
t
tc
t
r1
Section A–A
A
(g)
r1 = 1/8t to 1/2t
3/ in. (19 mm)
r2
4
1/ in. (6 mm)
r4
4
t = nominal thickness of shell or head
tc
0.7tn or 1/4 in. (6 mm), whichever is less
tn = nominal thickness of nozzle
236
Sections perpendicular
and parallel to the
cylindrical vessel axis
2010 SECTION VIII — DIVISION 1
TABLE UHT-23
FERRITIC STEELS WITH PROPERTIES ENHANCED BY HEAT TREATMENT
Spec.
No.
Spec.
No.
Type/Grade
Type/Grade
SA-333
8
SA-522
I
SA-334
8
SA-533
B Cl. 3, D Cl. 3
SA-353
...
SA-543
B, C
SA-420
WPL8
SA-553
I, II
SA-487
4 Cl. B & E, CA6NM Cl. A
SA-592
A, E, F
SA-508
4N Cl. 1 & 2
SA-645
A
SA-517
A, B, E, F, J, P
SA-724
A, B, C
GENERAL NOTE: Maximum allowable stress values in tension for the materials listed in the above table
are contained in Subpart 1 of Section II, Part D (see UG-23).
(see UG-23). For vessels designed to operate at a temperature colder than −20°F (−29°C), the allowable stress values
to be used in design shall not exceed those given for temperatures of −20°F (−29°C) to 100°F (38°C).
(b) Shells of pressure vessels may be made from welded
pipe or tubing listed in Table 1A.
SA-553, and SA-645, Grade A, shall be of the material
covered by these specifications or austenitic stainless steel
of the type which cannot be hardened by heat treatment.
If suitable austenitic stainless steel is used for permanent
attachments, consideration should be given to the greater
coefficient of expansion of the austenitic stainless steel.
UHT-25
UHT-29
CORROSION ALLOWANCE
Provision for possible deterioration due to the environment in which the vessel operates is the responsibility of
the designer.
UHT-27
Rules covering the design of stiffening rings are given
in UG-29. The design shall be based on the appropriate
figure in Subpart 3 of Section II, Part D for the material
used in the ring.
THICKNESS OF SHELLS UNDER
EXTERNAL PRESSURE
UHT-30
(a) Cylindrical and spherical shells under external pressure shall be designed by the rules in UG-28, using the
applicable figures in Subpart 3 of Section II, Part D and
the temperature limits of UG-20(c).
(b) Examples illustrating the use of the charts in the
figures for the design of vessels under external pressure
are given in Appendix L.
UHT-28
ATTACHMENT OF STIFFENING
RINGS TO SHELLS
Rules covering the attachment of stiffening rings are
given in UG-30. Attachments shall be made using a welding procedure qualified to Section IX for vessels constructed to Part UHT.
UHT-32
(10)
STIFFENING RINGS FOR SHELLS
UNDER EXTERNAL PRESSURE
STRUCTURAL ATTACHMENTS AND
STIFFENING RINGS
FORMED HEADS, PRESSURE ON
CONCAVE SIDE
Except as provided in UG-32(e) and 1-4(c) and (d),
formed heads shall be limited to ellipsoidal and /or hemispherical heads designed in accordance with UG-32(d)
or (f).
(a) Except as permitted in (b) below, all structural
attachments and stiffening rings which are welded directly
to pressure parts shall be made of materials of specified
minimum yield strength within ±20% of that of the material
to which they are attached.
(b) All permanent structural attachments welded
directly to shells or heads constructed of materials conforming to SA-333 Grade 8, SA-334 Grade 8, SA-353, SA-522,
UHT-33
FORMED HEADS, PRESSURE ON
CONVEX SIDE
Ellipsoidal, hemispherical, and conical heads having
pressure on the convex side (minus heads) shall be designed
237
(10)
2010 SECTION VIII — DIVISION 1
by the rules of UG-33, using the applicable external pressure charts referenced in Table 1A of Section II, Part D
and given in Subpart 3 of Section II, Part D.
UHT-34
attachment of the head or shell [see UHT-56(b) and (c)].
(e) When material of SA-333 Grade 8, SA-334 Grade
8, SA-353, SA-522, SA-553, and SA-645, Grade A are
postweld heat treated, the complete vessel or vessel component being so heat treated shall be maintained within the
permissible temperature range defined in Table UHT-56.
HEMISPHERICAL HEADS
When hemispherical heads are used, the head-to-shell
transition of Fig. UW-13.1 sketch (j) or Fig. UW-13.1
sketch (l) shall be used. When the weld is in or adjacent
to the tapered section, it shall be finished in a manner that
will maintain the required uniform slope for the full length
of the tapered section.
UHT-40
UHT-57
(a) Radiography. Radiographic examination for the
complete length of weld in accordance with the requirements of UW-51 is required for all welded joints of Type
No. (1) of Table UW-12. The required radiographic examination shall be made after any corrosion-resistant alloy
cover weld has been deposited.
(b) Nozzle Attachment Welds. Nozzle attachment welds
as provided for in UHT-18, Figs. UHT-18.1 and UHT-18.2
shall be radiographically examined in accordance with the
requirements of UW-51, except that Fig. UHT-18.2 type
nozzles having an inside diameter of 2 in. (50 mm) or less
shall be examined by a magnetic particle or liquid penetrant
method. For nozzle attachments illustrated as sketches (a),
(b), and (f) of Fig. UHT-18.2, the exposed cross section
of the vessel wall at the opening shall be included in the
examination.
(c) All corrosion resistant overlay weld deposits shall
be examined by the liquid penetrant method.
(d) Magnetic Particle Method. All welds, including
welds for attaching nonpressure parts to heat treated steels
covered by this Part, shall be examined by the magnetic
particle method after the hydrostatic test, except that those
surfaces not accessible after the hydrostatic test shall be
examined by the magnetic particle method at the last feasible stage of vessel fabrication. A magnetization method
shall be used that will avoid arc strikes. Cracks shall be
repaired or removed.
(e) Liquid Penetrant Method. As an acceptable alternative to magnetic particle examination or when magnetic
particle methods are not feasible because of the nonmagnetic character of the weld deposits, a liquid penetrant
method shall be used. For vessels constructed of SA-333
Grade 8, SA-334 Grade 8, SA-353, SA-522, SA-553
Grades A and B, and SA-645 materials, welds not examined radiographically shall be examined by the liquid penetrant method either before or after the hydrotest. Cracks are
unacceptable and shall be repaired or removed. Relevant
indications are those which result from imperfections. Linear indications are those indications in which the length
is more than three times the width. Any relevant linear
indications greater than 1⁄16 in. (1.5 mm) shall be repaired
or removed.
MATERIALS HAVING DIFFERENT
COEFFICIENTS OF EXPANSION
When welding materials with austenitic electrodes, the
differences between the coefficients of expansion and the
strengths of the base material and the weld metal should
be carefully considered, particularly for applications
involving cyclic stresses.
(10)
UHT-56
EXAMINATION
POSTWELD HEAT TREATMENT
(a) Before applying the detailed requirements and
exemptions in these paragraphs, satisfactory weld procedure qualifications of the procedures to be used shall be
performed in accordance with all of the variables in Section
IX including conditions of postweld heat treatment or lack
of postweld heat treatment and including restrictions listed
below. When determining the thickness requiring postweld
treatment in Table UHT-56